Highest Radon Risk Counties in America
The EPA classifies 1074 counties across 38 states as Zone 1 — the highest radon risk category. These counties have predicted average indoor radon screening levels above 4 pCi/L, the EPA's recommended action level for mitigation.
Zone 1 doesn't mean every home has dangerous radon levels, but it means the probability is significantly higher. Homes in these counties should be tested as a matter of course, especially before purchase. Radon mitigation systems are effective and typically cost $800–$2,500 to install.
The list below shows every Zone 1 county in the United States, organized by state. Click any county to see detailed radon information, testing recommendations, and neighboring county data.
Alabama
13 of 67 counties (19%) are Zone 1.
| County | Zone | Risk Level |
|---|---|---|
| Calhoun County | Zone 1 | Highest Potential |
| Clay County | Zone 1 | Highest Potential |
| Cleburne County | Zone 1 | Highest Potential |
| Colbert County | Zone 1 | Highest Potential |
| Coosa County | Zone 1 | Highest Potential |
| Franklin County | Zone 1 | Highest Potential |
| Jackson County | Zone 1 | Highest Potential |
| Lauderdale County | Zone 1 | Highest Potential |
| Lawrence County | Zone 1 | Highest Potential |
| Limestone County | Zone 1 | Highest Potential |
| Madison County | Zone 1 | Highest Potential |
| Morgan County | Zone 1 | Highest Potential |
| Talladega County | Zone 1 | Highest Potential |
California
2 of 58 counties (3%) are Zone 1.
| County | Zone | Risk Level |
|---|---|---|
| Santa Barbara County | Zone 1 | Highest Potential |
| Ventura County | Zone 1 | Highest Potential |
Colorado
53 of 64 counties (83%) are Zone 1.
| County | Zone | Risk Level |
|---|---|---|
| Adams County | Zone 1 | Highest Potential |
| Arapahoe County | Zone 1 | Highest Potential |
| Baca County | Zone 1 | Highest Potential |
| Bent County | Zone 1 | Highest Potential |
| Boulder County | Zone 1 | Highest Potential |
| Broomfield County | Zone 1 | Highest Potential |
| Chaffee County | Zone 1 | Highest Potential |
| Cheyenne County | Zone 1 | Highest Potential |
| Clear Creek County | Zone 1 | Highest Potential |
| Crowley County | Zone 1 | Highest Potential |
| Custer County | Zone 1 | Highest Potential |
| Delta County | Zone 1 | Highest Potential |
| Denver County | Zone 1 | Highest Potential |
| Dolores County | Zone 1 | Highest Potential |
| Douglas County | Zone 1 | Highest Potential |
| Elbert County | Zone 1 | Highest Potential |
| El Paso County | Zone 1 | Highest Potential |
| Fremont County | Zone 1 | Highest Potential |
| Garfield County | Zone 1 | Highest Potential |
| Gilpin County | Zone 1 | Highest Potential |
| Grand County | Zone 1 | Highest Potential |
| Gunnison County | Zone 1 | Highest Potential |
| Huerfano County | Zone 1 | Highest Potential |
| Jackson County | Zone 1 | Highest Potential |
| Jefferson County | Zone 1 | Highest Potential |
| Kiowa County | Zone 1 | Highest Potential |
| Kit Carson County | Zone 1 | Highest Potential |
| Lake County | Zone 1 | Highest Potential |
| La Plata County | Zone 1 | Highest Potential |
| Larimer County | Zone 1 | Highest Potential |
| Las Animas County | Zone 1 | Highest Potential |
| Lincoln County | Zone 1 | Highest Potential |
| Logan County | Zone 1 | Highest Potential |
| Mesa County | Zone 1 | Highest Potential |
| Moffat County | Zone 1 | Highest Potential |
| Montezuma County | Zone 1 | Highest Potential |
| Montrose County | Zone 1 | Highest Potential |
| Morgan County | Zone 1 | Highest Potential |
| Otero County | Zone 1 | Highest Potential |
| Ouray County | Zone 1 | Highest Potential |
| Park County | Zone 1 | Highest Potential |
| Phillips County | Zone 1 | Highest Potential |
| Pitkin County | Zone 1 | Highest Potential |
| Prowers County | Zone 1 | Highest Potential |
| Pueblo County | Zone 1 | Highest Potential |
| Rio Blanco County | Zone 1 | Highest Potential |
| San Miguel County | Zone 1 | Highest Potential |
| Sedgwick County | Zone 1 | Highest Potential |
| Summit County | Zone 1 | Highest Potential |
| Teller County | Zone 1 | Highest Potential |
| Washington County | Zone 1 | Highest Potential |
| Weld County | Zone 1 | Highest Potential |
| Yuma County | Zone 1 | Highest Potential |
Connecticut
4 of 8 counties (50%) are Zone 1.
| County | Zone | Risk Level |
|---|---|---|
| Fairfield County | Zone 1 | Highest Potential |
| Middlesex County | Zone 1 | Highest Potential |
| New Haven County | Zone 1 | Highest Potential |
| New London County | Zone 1 | Highest Potential |
Georgia
4 of 159 counties (3%) are Zone 1.
| County | Zone | Risk Level |
|---|---|---|
| Cobb County | Zone 1 | Highest Potential |
| DeKalb County | Zone 1 | Highest Potential |
| Fulton County | Zone 1 | Highest Potential |
| Gwinnett County | Zone 1 | Highest Potential |
Iowa
99 of 99 counties (100%) are Zone 1.
| County | Zone | Risk Level |
|---|---|---|
| Adair County | Zone 1 | Highest Potential |
| Adams County | Zone 1 | Highest Potential |
| Allamakee County | Zone 1 | Highest Potential |
| Appanoose County | Zone 1 | Highest Potential |
| Audubon County | Zone 1 | Highest Potential |
| Benton County | Zone 1 | Highest Potential |
| Black Hawk County | Zone 1 | Highest Potential |
| Boone County | Zone 1 | Highest Potential |
| Bremer County | Zone 1 | Highest Potential |
| Buchanan County | Zone 1 | Highest Potential |
| Buena Vista County | Zone 1 | Highest Potential |
| Butler County | Zone 1 | Highest Potential |
| Calhoun County | Zone 1 | Highest Potential |
| Carroll County | Zone 1 | Highest Potential |
| Cass County | Zone 1 | Highest Potential |
| Cedar County | Zone 1 | Highest Potential |
| Cerro Gordo County | Zone 1 | Highest Potential |
| Cherokee County | Zone 1 | Highest Potential |
| Chickasaw County | Zone 1 | Highest Potential |
| Clarke County | Zone 1 | Highest Potential |
| Clay County | Zone 1 | Highest Potential |
| Clayton County | Zone 1 | Highest Potential |
| Clinton County | Zone 1 | Highest Potential |
| Crawford County | Zone 1 | Highest Potential |
| Dallas County | Zone 1 | Highest Potential |
| Davis County | Zone 1 | Highest Potential |
| Decatur County | Zone 1 | Highest Potential |
| Delaware County | Zone 1 | Highest Potential |
| Des Moines County | Zone 1 | Highest Potential |
| Dickinson County | Zone 1 | Highest Potential |
| Dubuque County | Zone 1 | Highest Potential |
| Emmet County | Zone 1 | Highest Potential |
| Fayette County | Zone 1 | Highest Potential |
| Floyd County | Zone 1 | Highest Potential |
| Franklin County | Zone 1 | Highest Potential |
| Fremont County | Zone 1 | Highest Potential |
| Greene County | Zone 1 | Highest Potential |
| Grundy County | Zone 1 | Highest Potential |
| Guthrie County | Zone 1 | Highest Potential |
| Hamilton County | Zone 1 | Highest Potential |
| Hancock County | Zone 1 | Highest Potential |
| Hardin County | Zone 1 | Highest Potential |
| Harrison County | Zone 1 | Highest Potential |
| Henry County | Zone 1 | Highest Potential |
| Howard County | Zone 1 | Highest Potential |
| Humboldt County | Zone 1 | Highest Potential |
| Ida County | Zone 1 | Highest Potential |
| Iowa County | Zone 1 | Highest Potential |
| Jackson County | Zone 1 | Highest Potential |
| Jasper County | Zone 1 | Highest Potential |
| Jefferson County | Zone 1 | Highest Potential |
| Johnson County | Zone 1 | Highest Potential |
| Jones County | Zone 1 | Highest Potential |
| Keokuk County | Zone 1 | Highest Potential |
| Kossuth County | Zone 1 | Highest Potential |
| Lee County | Zone 1 | Highest Potential |
| Linn County | Zone 1 | Highest Potential |
| Louisa County | Zone 1 | Highest Potential |
| Lucas County | Zone 1 | Highest Potential |
| Lyon County | Zone 1 | Highest Potential |
| Madison County | Zone 1 | Highest Potential |
| Mahaska County | Zone 1 | Highest Potential |
| Marion County | Zone 1 | Highest Potential |
| Marshall County | Zone 1 | Highest Potential |
| Mills County | Zone 1 | Highest Potential |
| Mitchell County | Zone 1 | Highest Potential |
| Monona County | Zone 1 | Highest Potential |
| Monroe County | Zone 1 | Highest Potential |
| Montgomery County | Zone 1 | Highest Potential |
| Muscatine County | Zone 1 | Highest Potential |
| O'Brien County | Zone 1 | Highest Potential |
| Osceola County | Zone 1 | Highest Potential |
| Page County | Zone 1 | Highest Potential |
| Palo Alto County | Zone 1 | Highest Potential |
| Plymouth County | Zone 1 | Highest Potential |
| Pocahontas County | Zone 1 | Highest Potential |
| Polk County | Zone 1 | Highest Potential |
| Pottawattamie County | Zone 1 | Highest Potential |
| Poweshiek County | Zone 1 | Highest Potential |
| Ringgold County | Zone 1 | Highest Potential |
| Sac County | Zone 1 | Highest Potential |
| Scott County | Zone 1 | Highest Potential |
| Shelby County | Zone 1 | Highest Potential |
| Sioux County | Zone 1 | Highest Potential |
| Story County | Zone 1 | Highest Potential |
| Tama County | Zone 1 | Highest Potential |
| Taylor County | Zone 1 | Highest Potential |
| Union County | Zone 1 | Highest Potential |
| Van Buren County | Zone 1 | Highest Potential |
| Wapello County | Zone 1 | Highest Potential |
| Warren County | Zone 1 | Highest Potential |
| Washington County | Zone 1 | Highest Potential |
| Wayne County | Zone 1 | Highest Potential |
| Webster County | Zone 1 | Highest Potential |
| Winnebago County | Zone 1 | Highest Potential |
| Winneshiek County | Zone 1 | Highest Potential |
| Woodbury County | Zone 1 | Highest Potential |
| Worth County | Zone 1 | Highest Potential |
| Wright County | Zone 1 | Highest Potential |
Idaho
19 of 44 counties (43%) are Zone 1.
| County | Zone | Risk Level |
|---|---|---|
| Benewah County | Zone 1 | Highest Potential |
| Blaine County | Zone 1 | Highest Potential |
| Boise County | Zone 1 | Highest Potential |
| Bonner County | Zone 1 | Highest Potential |
| Boundary County | Zone 1 | Highest Potential |
| Butte County | Zone 1 | Highest Potential |
| Camas County | Zone 1 | Highest Potential |
| Clark County | Zone 1 | Highest Potential |
| Clearwater County | Zone 1 | Highest Potential |
| Custer County | Zone 1 | Highest Potential |
| Elmore County | Zone 1 | Highest Potential |
| Fremont County | Zone 1 | Highest Potential |
| Gooding County | Zone 1 | Highest Potential |
| Idaho County | Zone 1 | Highest Potential |
| Kootenai County | Zone 1 | Highest Potential |
| Latah County | Zone 1 | Highest Potential |
| Lemhi County | Zone 1 | Highest Potential |
| Shoshone County | Zone 1 | Highest Potential |
| Valley County | Zone 1 | Highest Potential |
Illinois
56 of 102 counties (55%) are Zone 1.
| County | Zone | Risk Level |
|---|---|---|
| Adams County | Zone 1 | Highest Potential |
| Boone County | Zone 1 | Highest Potential |
| Brown County | Zone 1 | Highest Potential |
| Bureau County | Zone 1 | Highest Potential |
| Calhoun County | Zone 1 | Highest Potential |
| Carroll County | Zone 1 | Highest Potential |
| Cass County | Zone 1 | Highest Potential |
| Champaign County | Zone 1 | Highest Potential |
| Coles County | Zone 1 | Highest Potential |
| DeKalb County | Zone 1 | Highest Potential |
| De Witt County | Zone 1 | Highest Potential |
| Douglas County | Zone 1 | Highest Potential |
| Edgar County | Zone 1 | Highest Potential |
| Ford County | Zone 1 | Highest Potential |
| Fulton County | Zone 1 | Highest Potential |
| Greene County | Zone 1 | Highest Potential |
| Grundy County | Zone 1 | Highest Potential |
| Hancock County | Zone 1 | Highest Potential |
| Henderson County | Zone 1 | Highest Potential |
| Henry County | Zone 1 | Highest Potential |
| Iroquois County | Zone 1 | Highest Potential |
| Jersey County | Zone 1 | Highest Potential |
| Jo Daviess County | Zone 1 | Highest Potential |
| Kane County | Zone 1 | Highest Potential |
| Kendall County | Zone 1 | Highest Potential |
| Knox County | Zone 1 | Highest Potential |
| LaSalle County | Zone 1 | Highest Potential |
| Lee County | Zone 1 | Highest Potential |
| Livingston County | Zone 1 | Highest Potential |
| Logan County | Zone 1 | Highest Potential |
| McDonough County | Zone 1 | Highest Potential |
| McLean County | Zone 1 | Highest Potential |
| Macon County | Zone 1 | Highest Potential |
| Marshall County | Zone 1 | Highest Potential |
| Mason County | Zone 1 | Highest Potential |
| Menard County | Zone 1 | Highest Potential |
| Mercer County | Zone 1 | Highest Potential |
| Morgan County | Zone 1 | Highest Potential |
| Moultrie County | Zone 1 | Highest Potential |
| Ogle County | Zone 1 | Highest Potential |
| Peoria County | Zone 1 | Highest Potential |
| Piatt County | Zone 1 | Highest Potential |
| Pike County | Zone 1 | Highest Potential |
| Putnam County | Zone 1 | Highest Potential |
| Rock Island County | Zone 1 | Highest Potential |
| Sangamon County | Zone 1 | Highest Potential |
| Schuyler County | Zone 1 | Highest Potential |
| Scott County | Zone 1 | Highest Potential |
| Stark County | Zone 1 | Highest Potential |
| Stephenson County | Zone 1 | Highest Potential |
| Tazewell County | Zone 1 | Highest Potential |
| Vermilion County | Zone 1 | Highest Potential |
| Warren County | Zone 1 | Highest Potential |
| Whiteside County | Zone 1 | Highest Potential |
| Winnebago County | Zone 1 | Highest Potential |
| Woodford County | Zone 1 | Highest Potential |
Indiana
57 of 92 counties (62%) are Zone 1.
| County | Zone | Risk Level |
|---|---|---|
| Adams County | Zone 1 | Highest Potential |
| Allen County | Zone 1 | Highest Potential |
| Bartholomew County | Zone 1 | Highest Potential |
| Benton County | Zone 1 | Highest Potential |
| Blackford County | Zone 1 | Highest Potential |
| Boone County | Zone 1 | Highest Potential |
| Carroll County | Zone 1 | Highest Potential |
| Cass County | Zone 1 | Highest Potential |
| Clark County | Zone 1 | Highest Potential |
| Clinton County | Zone 1 | Highest Potential |
| Decatur County | Zone 1 | Highest Potential |
| DeKalb County | Zone 1 | Highest Potential |
| Delaware County | Zone 1 | Highest Potential |
| Elkhart County | Zone 1 | Highest Potential |
| Fayette County | Zone 1 | Highest Potential |
| Fountain County | Zone 1 | Highest Potential |
| Fulton County | Zone 1 | Highest Potential |
| Grant County | Zone 1 | Highest Potential |
| Hamilton County | Zone 1 | Highest Potential |
| Hancock County | Zone 1 | Highest Potential |
| Harrison County | Zone 1 | Highest Potential |
| Hendricks County | Zone 1 | Highest Potential |
| Henry County | Zone 1 | Highest Potential |
| Howard County | Zone 1 | Highest Potential |
| Huntington County | Zone 1 | Highest Potential |
| Jay County | Zone 1 | Highest Potential |
| Jennings County | Zone 1 | Highest Potential |
| Johnson County | Zone 1 | Highest Potential |
| Kosciusko County | Zone 1 | Highest Potential |
| LaGrange County | Zone 1 | Highest Potential |
| Lawrence County | Zone 1 | Highest Potential |
| Madison County | Zone 1 | Highest Potential |
| Marion County | Zone 1 | Highest Potential |
| Marshall County | Zone 1 | Highest Potential |
| Miami County | Zone 1 | Highest Potential |
| Monroe County | Zone 1 | Highest Potential |
| Montgomery County | Zone 1 | Highest Potential |
| Noble County | Zone 1 | Highest Potential |
| Orange County | Zone 1 | Highest Potential |
| Putnam County | Zone 1 | Highest Potential |
| Randolph County | Zone 1 | Highest Potential |
| Rush County | Zone 1 | Highest Potential |
| St. Joseph County | Zone 1 | Highest Potential |
| Scott County | Zone 1 | Highest Potential |
| Shelby County | Zone 1 | Highest Potential |
| Steuben County | Zone 1 | Highest Potential |
| Tippecanoe County | Zone 1 | Highest Potential |
| Tipton County | Zone 1 | Highest Potential |
| Union County | Zone 1 | Highest Potential |
| Vermillion County | Zone 1 | Highest Potential |
| Wabash County | Zone 1 | Highest Potential |
| Warren County | Zone 1 | Highest Potential |
| Washington County | Zone 1 | Highest Potential |
| Wayne County | Zone 1 | Highest Potential |
| Wells County | Zone 1 | Highest Potential |
| White County | Zone 1 | Highest Potential |
| Whitley County | Zone 1 | Highest Potential |
Kansas
65 of 105 counties (62%) are Zone 1.
| County | Zone | Risk Level |
|---|---|---|
| Atchison County | Zone 1 | Highest Potential |
| Barton County | Zone 1 | Highest Potential |
| Brown County | Zone 1 | Highest Potential |
| Cheyenne County | Zone 1 | Highest Potential |
| Clay County | Zone 1 | Highest Potential |
| Cloud County | Zone 1 | Highest Potential |
| Decatur County | Zone 1 | Highest Potential |
| Dickinson County | Zone 1 | Highest Potential |
| Douglas County | Zone 1 | Highest Potential |
| Ellis County | Zone 1 | Highest Potential |
| Ellsworth County | Zone 1 | Highest Potential |
| Finney County | Zone 1 | Highest Potential |
| Ford County | Zone 1 | Highest Potential |
| Geary County | Zone 1 | Highest Potential |
| Gove County | Zone 1 | Highest Potential |
| Graham County | Zone 1 | Highest Potential |
| Grant County | Zone 1 | Highest Potential |
| Gray County | Zone 1 | Highest Potential |
| Greeley County | Zone 1 | Highest Potential |
| Hamilton County | Zone 1 | Highest Potential |
| Haskell County | Zone 1 | Highest Potential |
| Hodgeman County | Zone 1 | Highest Potential |
| Jackson County | Zone 1 | Highest Potential |
| Jewell County | Zone 1 | Highest Potential |
| Johnson County | Zone 1 | Highest Potential |
| Kearny County | Zone 1 | Highest Potential |
| Kingman County | Zone 1 | Highest Potential |
| Kiowa County | Zone 1 | Highest Potential |
| Lane County | Zone 1 | Highest Potential |
| Leavenworth County | Zone 1 | Highest Potential |
| Lincoln County | Zone 1 | Highest Potential |
| Logan County | Zone 1 | Highest Potential |
| McPherson County | Zone 1 | Highest Potential |
| Marion County | Zone 1 | Highest Potential |
| Marshall County | Zone 1 | Highest Potential |
| Meade County | Zone 1 | Highest Potential |
| Mitchell County | Zone 1 | Highest Potential |
| Nemaha County | Zone 1 | Highest Potential |
| Ness County | Zone 1 | Highest Potential |
| Norton County | Zone 1 | Highest Potential |
| Osborne County | Zone 1 | Highest Potential |
| Ottawa County | Zone 1 | Highest Potential |
| Pawnee County | Zone 1 | Highest Potential |
| Phillips County | Zone 1 | Highest Potential |
| Pottawatomie County | Zone 1 | Highest Potential |
| Pratt County | Zone 1 | Highest Potential |
| Rawlins County | Zone 1 | Highest Potential |
| Republic County | Zone 1 | Highest Potential |
| Rice County | Zone 1 | Highest Potential |
| Riley County | Zone 1 | Highest Potential |
| Rooks County | Zone 1 | Highest Potential |
| Rush County | Zone 1 | Highest Potential |
| Russell County | Zone 1 | Highest Potential |
| Saline County | Zone 1 | Highest Potential |
| Scott County | Zone 1 | Highest Potential |
| Sheridan County | Zone 1 | Highest Potential |
| Sherman County | Zone 1 | Highest Potential |
| Smith County | Zone 1 | Highest Potential |
| Stanton County | Zone 1 | Highest Potential |
| Thomas County | Zone 1 | Highest Potential |
| Trego County | Zone 1 | Highest Potential |
| Wallace County | Zone 1 | Highest Potential |
| Washington County | Zone 1 | Highest Potential |
| Wichita County | Zone 1 | Highest Potential |
| Wyandotte County | Zone 1 | Highest Potential |
Kentucky
30 of 120 counties (25%) are Zone 1.
| County | Zone | Risk Level |
|---|---|---|
| Adair County | Zone 1 | Highest Potential |
| Allen County | Zone 1 | Highest Potential |
| Barren County | Zone 1 | Highest Potential |
| Bourbon County | Zone 1 | Highest Potential |
| Boyle County | Zone 1 | Highest Potential |
| Bullitt County | Zone 1 | Highest Potential |
| Casey County | Zone 1 | Highest Potential |
| Clark County | Zone 1 | Highest Potential |
| Cumberland County | Zone 1 | Highest Potential |
| Fayette County | Zone 1 | Highest Potential |
| Franklin County | Zone 1 | Highest Potential |
| Green County | Zone 1 | Highest Potential |
| Harrison County | Zone 1 | Highest Potential |
| Hart County | Zone 1 | Highest Potential |
| Jefferson County | Zone 1 | Highest Potential |
| Jessamine County | Zone 1 | Highest Potential |
| Lincoln County | Zone 1 | Highest Potential |
| Marion County | Zone 1 | Highest Potential |
| Mercer County | Zone 1 | Highest Potential |
| Metcalfe County | Zone 1 | Highest Potential |
| Monroe County | Zone 1 | Highest Potential |
| Nelson County | Zone 1 | Highest Potential |
| Pendleton County | Zone 1 | Highest Potential |
| Pulaski County | Zone 1 | Highest Potential |
| Robertson County | Zone 1 | Highest Potential |
| Russell County | Zone 1 | Highest Potential |
| Scott County | Zone 1 | Highest Potential |
| Taylor County | Zone 1 | Highest Potential |
| Warren County | Zone 1 | Highest Potential |
| Woodford County | Zone 1 | Highest Potential |
Massachusetts
3 of 14 counties (21%) are Zone 1.
| County | Zone | Risk Level |
|---|---|---|
| Essex County | Zone 1 | Highest Potential |
| Middlesex County | Zone 1 | Highest Potential |
| Worcester County | Zone 1 | Highest Potential |
Maryland
8 of 24 counties (33%) are Zone 1.
| County | Zone | Risk Level |
|---|---|---|
| Baltimore County | Zone 1 | Highest Potential |
| Calvert County | Zone 1 | Highest Potential |
| Carroll County | Zone 1 | Highest Potential |
| Frederick County | Zone 1 | Highest Potential |
| Harford County | Zone 1 | Highest Potential |
| Howard County | Zone 1 | Highest Potential |
| Montgomery County | Zone 1 | Highest Potential |
| Washington County | Zone 1 | Highest Potential |
Maine
12 of 16 counties (75%) are Zone 1.
| County | Zone | Risk Level |
|---|---|---|
| Androscoggin County | Zone 1 | Highest Potential |
| Aroostook County | Zone 1 | Highest Potential |
| Cumberland County | Zone 1 | Highest Potential |
| Franklin County | Zone 1 | Highest Potential |
| Hancock County | Zone 1 | Highest Potential |
| Kennebec County | Zone 1 | Highest Potential |
| Lincoln County | Zone 1 | Highest Potential |
| Oxford County | Zone 1 | Highest Potential |
| Penobscot County | Zone 1 | Highest Potential |
| Piscataquis County | Zone 1 | Highest Potential |
| Somerset County | Zone 1 | Highest Potential |
| York County | Zone 1 | Highest Potential |
Michigan
9 of 83 counties (11%) are Zone 1.
| County | Zone | Risk Level |
|---|---|---|
| Branch County | Zone 1 | Highest Potential |
| Calhoun County | Zone 1 | Highest Potential |
| Cass County | Zone 1 | Highest Potential |
| Hillsdale County | Zone 1 | Highest Potential |
| Jackson County | Zone 1 | Highest Potential |
| Kalamazoo County | Zone 1 | Highest Potential |
| Lenawee County | Zone 1 | Highest Potential |
| St. Joseph County | Zone 1 | Highest Potential |
| Washtenaw County | Zone 1 | Highest Potential |
Minnesota
68 of 87 counties (78%) are Zone 1.
| County | Zone | Risk Level |
|---|---|---|
| Becker County | Zone 1 | Highest Potential |
| Big Stone County | Zone 1 | Highest Potential |
| Blue Earth County | Zone 1 | Highest Potential |
| Brown County | Zone 1 | Highest Potential |
| Carver County | Zone 1 | Highest Potential |
| Chippewa County | Zone 1 | Highest Potential |
| Clay County | Zone 1 | Highest Potential |
| Cottonwood County | Zone 1 | Highest Potential |
| Dakota County | Zone 1 | Highest Potential |
| Dodge County | Zone 1 | Highest Potential |
| Douglas County | Zone 1 | Highest Potential |
| Faribault County | Zone 1 | Highest Potential |
| Fillmore County | Zone 1 | Highest Potential |
| Freeborn County | Zone 1 | Highest Potential |
| Goodhue County | Zone 1 | Highest Potential |
| Grant County | Zone 1 | Highest Potential |
| Hennepin County | Zone 1 | Highest Potential |
| Houston County | Zone 1 | Highest Potential |
| Hubbard County | Zone 1 | Highest Potential |
| Jackson County | Zone 1 | Highest Potential |
| Kanabec County | Zone 1 | Highest Potential |
| Kandiyohi County | Zone 1 | Highest Potential |
| Kittson County | Zone 1 | Highest Potential |
| Lac qui Parle County | Zone 1 | Highest Potential |
| Le Sueur County | Zone 1 | Highest Potential |
| Lincoln County | Zone 1 | Highest Potential |
| Lyon County | Zone 1 | Highest Potential |
| McLeod County | Zone 1 | Highest Potential |
| Mahnomen County | Zone 1 | Highest Potential |
| Marshall County | Zone 1 | Highest Potential |
| Martin County | Zone 1 | Highest Potential |
| Meeker County | Zone 1 | Highest Potential |
| Mower County | Zone 1 | Highest Potential |
| Murray County | Zone 1 | Highest Potential |
| Nicollet County | Zone 1 | Highest Potential |
| Nobles County | Zone 1 | Highest Potential |
| Norman County | Zone 1 | Highest Potential |
| Olmsted County | Zone 1 | Highest Potential |
| Otter Tail County | Zone 1 | Highest Potential |
| Pennington County | Zone 1 | Highest Potential |
| Pipestone County | Zone 1 | Highest Potential |
| Polk County | Zone 1 | Highest Potential |
| Pope County | Zone 1 | Highest Potential |
| Ramsey County | Zone 1 | Highest Potential |
| Red Lake County | Zone 1 | Highest Potential |
| Redwood County | Zone 1 | Highest Potential |
| Renville County | Zone 1 | Highest Potential |
| Rice County | Zone 1 | Highest Potential |
| Rock County | Zone 1 | Highest Potential |
| Roseau County | Zone 1 | Highest Potential |
| Scott County | Zone 1 | Highest Potential |
| Sherburne County | Zone 1 | Highest Potential |
| Sibley County | Zone 1 | Highest Potential |
| Stearns County | Zone 1 | Highest Potential |
| Steele County | Zone 1 | Highest Potential |
| Stevens County | Zone 1 | Highest Potential |
| Swift County | Zone 1 | Highest Potential |
| Todd County | Zone 1 | Highest Potential |
| Traverse County | Zone 1 | Highest Potential |
| Wabasha County | Zone 1 | Highest Potential |
| Wadena County | Zone 1 | Highest Potential |
| Waseca County | Zone 1 | Highest Potential |
| Washington County | Zone 1 | Highest Potential |
| Watonwan County | Zone 1 | Highest Potential |
| Wilkin County | Zone 1 | Highest Potential |
| Winona County | Zone 1 | Highest Potential |
| Wright County | Zone 1 | Highest Potential |
| Yellow Medicine County | Zone 1 | Highest Potential |
Missouri
11 of 115 counties (10%) are Zone 1.
| County | Zone | Risk Level |
|---|---|---|
| Andrew County | Zone 1 | Highest Potential |
| Atchison County | Zone 1 | Highest Potential |
| Buchanan County | Zone 1 | Highest Potential |
| Cass County | Zone 1 | Highest Potential |
| Clay County | Zone 1 | Highest Potential |
| Clinton County | Zone 1 | Highest Potential |
| Holt County | Zone 1 | Highest Potential |
| Iron County | Zone 1 | Highest Potential |
| Jackson County | Zone 1 | Highest Potential |
| Nodaway County | Zone 1 | Highest Potential |
| Platte County | Zone 1 | Highest Potential |
Montana
50 of 57 counties (88%) are Zone 1.
| County | Zone | Risk Level |
|---|---|---|
| Beaverhead County | Zone 1 | Highest Potential |
| Big Horn County | Zone 1 | Highest Potential |
| Blaine County | Zone 1 | Highest Potential |
| Broadwater County | Zone 1 | Highest Potential |
| Carbon County | Zone 1 | Highest Potential |
| Carter County | Zone 1 | Highest Potential |
| Cascade County | Zone 1 | Highest Potential |
| Chouteau County | Zone 1 | Highest Potential |
| Custer County | Zone 1 | Highest Potential |
| Daniels County | Zone 1 | Highest Potential |
| Dawson County | Zone 1 | Highest Potential |
| Deer Lodge County | Zone 1 | Highest Potential |
| Fallon County | Zone 1 | Highest Potential |
| Fergus County | Zone 1 | Highest Potential |
| Flathead County | Zone 1 | Highest Potential |
| Gallatin County | Zone 1 | Highest Potential |
| Garfield County | Zone 1 | Highest Potential |
| Glacier County | Zone 1 | Highest Potential |
| Granite County | Zone 1 | Highest Potential |
| Hill County | Zone 1 | Highest Potential |
| Jefferson County | Zone 1 | Highest Potential |
| Judith Basin County | Zone 1 | Highest Potential |
| Lake County | Zone 1 | Highest Potential |
| Lewis and Clark County | Zone 1 | Highest Potential |
| Liberty County | Zone 1 | Highest Potential |
| Lincoln County | Zone 1 | Highest Potential |
| McCone County | Zone 1 | Highest Potential |
| Madison County | Zone 1 | Highest Potential |
| Meagher County | Zone 1 | Highest Potential |
| Mineral County | Zone 1 | Highest Potential |
| Missoula County | Zone 1 | Highest Potential |
| Park County | Zone 1 | Highest Potential |
| Phillips County | Zone 1 | Highest Potential |
| Pondera County | Zone 1 | Highest Potential |
| Powder River County | Zone 1 | Highest Potential |
| Powell County | Zone 1 | Highest Potential |
| Prairie County | Zone 1 | Highest Potential |
| Ravalli County | Zone 1 | Highest Potential |
| Richland County | Zone 1 | Highest Potential |
| Roosevelt County | Zone 1 | Highest Potential |
| Rosebud County | Zone 1 | Highest Potential |
| Sanders County | Zone 1 | Highest Potential |
| Sheridan County | Zone 1 | Highest Potential |
| Silver Bow County | Zone 1 | Highest Potential |
| Stillwater County | Zone 1 | Highest Potential |
| Teton County | Zone 1 | Highest Potential |
| Toole County | Zone 1 | Highest Potential |
| Valley County | Zone 1 | Highest Potential |
| Wibaux County | Zone 1 | Highest Potential |
| Yellowstone National Park, MT | Zone 1 | Highest Potential |
North Carolina
8 of 100 counties (8%) are Zone 1.
| County | Zone | Risk Level |
|---|---|---|
| Alleghany County | Zone 1 | Highest Potential |
| Buncombe County | Zone 1 | Highest Potential |
| Cherokee County | Zone 1 | Highest Potential |
| Henderson County | Zone 1 | Highest Potential |
| Mitchell County | Zone 1 | Highest Potential |
| Rockingham County | Zone 1 | Highest Potential |
| Transylvania County | Zone 1 | Highest Potential |
| Watauga County | Zone 1 | Highest Potential |
North Dakota
53 of 53 counties (100%) are Zone 1.
| County | Zone | Risk Level |
|---|---|---|
| Adams County | Zone 1 | Highest Potential |
| Barnes County | Zone 1 | Highest Potential |
| Benson County | Zone 1 | Highest Potential |
| Billings County | Zone 1 | Highest Potential |
| Bottineau County | Zone 1 | Highest Potential |
| Bowman County | Zone 1 | Highest Potential |
| Burke County | Zone 1 | Highest Potential |
| Burleigh County | Zone 1 | Highest Potential |
| Cass County | Zone 1 | Highest Potential |
| Cavalier County | Zone 1 | Highest Potential |
| Dickey County | Zone 1 | Highest Potential |
| Divide County | Zone 1 | Highest Potential |
| Dunn County | Zone 1 | Highest Potential |
| Eddy County | Zone 1 | Highest Potential |
| Emmons County | Zone 1 | Highest Potential |
| Foster County | Zone 1 | Highest Potential |
| Golden Valley County | Zone 1 | Highest Potential |
| Grand Forks County | Zone 1 | Highest Potential |
| Grant County | Zone 1 | Highest Potential |
| Griggs County | Zone 1 | Highest Potential |
| Hettinger County | Zone 1 | Highest Potential |
| Kidder County | Zone 1 | Highest Potential |
| LaMoure County | Zone 1 | Highest Potential |
| Logan County | Zone 1 | Highest Potential |
| McHenry County | Zone 1 | Highest Potential |
| McIntosh County | Zone 1 | Highest Potential |
| McKenzie County | Zone 1 | Highest Potential |
| McLean County | Zone 1 | Highest Potential |
| Mercer County | Zone 1 | Highest Potential |
| Morton County | Zone 1 | Highest Potential |
| Mountrail County | Zone 1 | Highest Potential |
| Nelson County | Zone 1 | Highest Potential |
| Oliver County | Zone 1 | Highest Potential |
| Pembina County | Zone 1 | Highest Potential |
| Pierce County | Zone 1 | Highest Potential |
| Ramsey County | Zone 1 | Highest Potential |
| Ransom County | Zone 1 | Highest Potential |
| Renville County | Zone 1 | Highest Potential |
| Richland County | Zone 1 | Highest Potential |
| Rolette County | Zone 1 | Highest Potential |
| Sargent County | Zone 1 | Highest Potential |
| Sheridan County | Zone 1 | Highest Potential |
| Sioux County | Zone 1 | Highest Potential |
| Slope County | Zone 1 | Highest Potential |
| Stark County | Zone 1 | Highest Potential |
| Steele County | Zone 1 | Highest Potential |
| Stutsman County | Zone 1 | Highest Potential |
| Towner County | Zone 1 | Highest Potential |
| Traill County | Zone 1 | Highest Potential |
| Walsh County | Zone 1 | Highest Potential |
| Ward County | Zone 1 | Highest Potential |
| Wells County | Zone 1 | Highest Potential |
| Williams County | Zone 1 | Highest Potential |
Nebraska
53 of 93 counties (57%) are Zone 1.
| County | Zone | Risk Level |
|---|---|---|
| Adams County | Zone 1 | Highest Potential |
| Boone County | Zone 1 | Highest Potential |
| Boyd County | Zone 1 | Highest Potential |
| Burt County | Zone 1 | Highest Potential |
| Butler County | Zone 1 | Highest Potential |
| Cass County | Zone 1 | Highest Potential |
| Cedar County | Zone 1 | Highest Potential |
| Clay County | Zone 1 | Highest Potential |
| Colfax County | Zone 1 | Highest Potential |
| Cuming County | Zone 1 | Highest Potential |
| Dakota County | Zone 1 | Highest Potential |
| Dixon County | Zone 1 | Highest Potential |
| Dodge County | Zone 1 | Highest Potential |
| Douglas County | Zone 1 | Highest Potential |
| Fillmore County | Zone 1 | Highest Potential |
| Franklin County | Zone 1 | Highest Potential |
| Frontier County | Zone 1 | Highest Potential |
| Furnas County | Zone 1 | Highest Potential |
| Gage County | Zone 1 | Highest Potential |
| Gosper County | Zone 1 | Highest Potential |
| Greeley County | Zone 1 | Highest Potential |
| Hamilton County | Zone 1 | Highest Potential |
| Harlan County | Zone 1 | Highest Potential |
| Hayes County | Zone 1 | Highest Potential |
| Hitchcock County | Zone 1 | Highest Potential |
| Jefferson County | Zone 1 | Highest Potential |
| Johnson County | Zone 1 | Highest Potential |
| Kearney County | Zone 1 | Highest Potential |
| Knox County | Zone 1 | Highest Potential |
| Lancaster County | Zone 1 | Highest Potential |
| Madison County | Zone 1 | Highest Potential |
| Nance County | Zone 1 | Highest Potential |
| Nemaha County | Zone 1 | Highest Potential |
| Nuckolls County | Zone 1 | Highest Potential |
| Otoe County | Zone 1 | Highest Potential |
| Pawnee County | Zone 1 | Highest Potential |
| Phelps County | Zone 1 | Highest Potential |
| Pierce County | Zone 1 | Highest Potential |
| Platte County | Zone 1 | Highest Potential |
| Polk County | Zone 1 | Highest Potential |
| Red Willow County | Zone 1 | Highest Potential |
| Richardson County | Zone 1 | Highest Potential |
| Saline County | Zone 1 | Highest Potential |
| Sarpy County | Zone 1 | Highest Potential |
| Saunders County | Zone 1 | Highest Potential |
| Seward County | Zone 1 | Highest Potential |
| Stanton County | Zone 1 | Highest Potential |
| Thayer County | Zone 1 | Highest Potential |
| Thurston County | Zone 1 | Highest Potential |
| Washington County | Zone 1 | Highest Potential |
| Wayne County | Zone 1 | Highest Potential |
| Webster County | Zone 1 | Highest Potential |
| York County | Zone 1 | Highest Potential |
New Hampshire
1 of 10 counties (10%) are Zone 1.
| County | Zone | Risk Level |
|---|---|---|
| Carroll County | Zone 1 | Highest Potential |
New Jersey
7 of 21 counties (33%) are Zone 1.
| County | Zone | Risk Level |
|---|---|---|
| Hunterdon County | Zone 1 | Highest Potential |
| Mercer County | Zone 1 | Highest Potential |
| Monmouth County | Zone 1 | Highest Potential |
| Morris County | Zone 1 | Highest Potential |
| Somerset County | Zone 1 | Highest Potential |
| Sussex County | Zone 1 | Highest Potential |
| Warren County | Zone 1 | Highest Potential |
New Mexico
7 of 33 counties (21%) are Zone 1.
| County | Zone | Risk Level |
|---|---|---|
| Bernalillo County | Zone 1 | Highest Potential |
| Colfax County | Zone 1 | Highest Potential |
| Mora County | Zone 1 | Highest Potential |
| Rio Arriba County | Zone 1 | Highest Potential |
| San Miguel County | Zone 1 | Highest Potential |
| Santa Fe County | Zone 1 | Highest Potential |
| Taos County | Zone 1 | Highest Potential |
Nevada
9 of 17 counties (53%) are Zone 1.
| County | Zone | Risk Level |
|---|---|---|
| Douglas County | Zone 1 | Highest Potential |
| Eureka County | Zone 1 | Highest Potential |
| Lander County | Zone 1 | Highest Potential |
| Lincoln County | Zone 1 | Highest Potential |
| Lyon County | Zone 1 | Highest Potential |
| Mineral County | Zone 1 | Highest Potential |
| Pershing County | Zone 1 | Highest Potential |
| White Pine County | Zone 1 | Highest Potential |
| Carson City | Zone 1 | Highest Potential |
New York
34 of 62 counties (55%) are Zone 1.
| County | Zone | Risk Level |
|---|---|---|
| Albany County | Zone 1 | Highest Potential |
| Allegany County | Zone 1 | Highest Potential |
| Broome County | Zone 1 | Highest Potential |
| Cattaraugus County | Zone 1 | Highest Potential |
| Cayuga County | Zone 1 | Highest Potential |
| Chautauqua County | Zone 1 | Highest Potential |
| Chemung County | Zone 1 | Highest Potential |
| Chenango County | Zone 1 | Highest Potential |
| Columbia County | Zone 1 | Highest Potential |
| Cortland County | Zone 1 | Highest Potential |
| Delaware County | Zone 1 | Highest Potential |
| Dutchess County | Zone 1 | Highest Potential |
| Erie County | Zone 1 | Highest Potential |
| Genesee County | Zone 1 | Highest Potential |
| Greene County | Zone 1 | Highest Potential |
| Livingston County | Zone 1 | Highest Potential |
| Madison County | Zone 1 | Highest Potential |
| Onondaga County | Zone 1 | Highest Potential |
| Ontario County | Zone 1 | Highest Potential |
| Orange County | Zone 1 | Highest Potential |
| Otsego County | Zone 1 | Highest Potential |
| Putnam County | Zone 1 | Highest Potential |
| Rensselaer County | Zone 1 | Highest Potential |
| Schoharie County | Zone 1 | Highest Potential |
| Schuyler County | Zone 1 | Highest Potential |
| Seneca County | Zone 1 | Highest Potential |
| Steuben County | Zone 1 | Highest Potential |
| Sullivan County | Zone 1 | Highest Potential |
| Tioga County | Zone 1 | Highest Potential |
| Tompkins County | Zone 1 | Highest Potential |
| Ulster County | Zone 1 | Highest Potential |
| Washington County | Zone 1 | Highest Potential |
| Wyoming County | Zone 1 | Highest Potential |
| Yates County | Zone 1 | Highest Potential |
Ohio
53 of 88 counties (60%) are Zone 1.
| County | Zone | Risk Level |
|---|---|---|
| Adams County | Zone 1 | Highest Potential |
| Allen County | Zone 1 | Highest Potential |
| Ashland County | Zone 1 | Highest Potential |
| Auglaize County | Zone 1 | Highest Potential |
| Belmont County | Zone 1 | Highest Potential |
| Butler County | Zone 1 | Highest Potential |
| Carroll County | Zone 1 | Highest Potential |
| Champaign County | Zone 1 | Highest Potential |
| Clark County | Zone 1 | Highest Potential |
| Clinton County | Zone 1 | Highest Potential |
| Columbiana County | Zone 1 | Highest Potential |
| Coshocton County | Zone 1 | Highest Potential |
| Crawford County | Zone 1 | Highest Potential |
| Darke County | Zone 1 | Highest Potential |
| Delaware County | Zone 1 | Highest Potential |
| Fairfield County | Zone 1 | Highest Potential |
| Fayette County | Zone 1 | Highest Potential |
| Franklin County | Zone 1 | Highest Potential |
| Greene County | Zone 1 | Highest Potential |
| Guernsey County | Zone 1 | Highest Potential |
| Hamilton County | Zone 1 | Highest Potential |
| Hancock County | Zone 1 | Highest Potential |
| Hardin County | Zone 1 | Highest Potential |
| Harrison County | Zone 1 | Highest Potential |
| Holmes County | Zone 1 | Highest Potential |
| Huron County | Zone 1 | Highest Potential |
| Jefferson County | Zone 1 | Highest Potential |
| Knox County | Zone 1 | Highest Potential |
| Licking County | Zone 1 | Highest Potential |
| Logan County | Zone 1 | Highest Potential |
| Madison County | Zone 1 | Highest Potential |
| Marion County | Zone 1 | Highest Potential |
| Mercer County | Zone 1 | Highest Potential |
| Miami County | Zone 1 | Highest Potential |
| Montgomery County | Zone 1 | Highest Potential |
| Morrow County | Zone 1 | Highest Potential |
| Muskingum County | Zone 1 | Highest Potential |
| Perry County | Zone 1 | Highest Potential |
| Pickaway County | Zone 1 | Highest Potential |
| Pike County | Zone 1 | Highest Potential |
| Preble County | Zone 1 | Highest Potential |
| Richland County | Zone 1 | Highest Potential |
| Ross County | Zone 1 | Highest Potential |
| Seneca County | Zone 1 | Highest Potential |
| Shelby County | Zone 1 | Highest Potential |
| Stark County | Zone 1 | Highest Potential |
| Summit County | Zone 1 | Highest Potential |
| Tuscarawas County | Zone 1 | Highest Potential |
| Union County | Zone 1 | Highest Potential |
| Van Wert County | Zone 1 | Highest Potential |
| Warren County | Zone 1 | Highest Potential |
| Wayne County | Zone 1 | Highest Potential |
| Wyandot County | Zone 1 | Highest Potential |
Pennsylvania
49 of 67 counties (73%) are Zone 1.
| County | Zone | Risk Level |
|---|---|---|
| Adams County | Zone 1 | Highest Potential |
| Allegheny County | Zone 1 | Highest Potential |
| Armstrong County | Zone 1 | Highest Potential |
| Beaver County | Zone 1 | Highest Potential |
| Bedford County | Zone 1 | Highest Potential |
| Berks County | Zone 1 | Highest Potential |
| Blair County | Zone 1 | Highest Potential |
| Bradford County | Zone 1 | Highest Potential |
| Bucks County | Zone 1 | Highest Potential |
| Butler County | Zone 1 | Highest Potential |
| Cameron County | Zone 1 | Highest Potential |
| Carbon County | Zone 1 | Highest Potential |
| Centre County | Zone 1 | Highest Potential |
| Chester County | Zone 1 | Highest Potential |
| Clarion County | Zone 1 | Highest Potential |
| Clearfield County | Zone 1 | Highest Potential |
| Clinton County | Zone 1 | Highest Potential |
| Columbia County | Zone 1 | Highest Potential |
| Cumberland County | Zone 1 | Highest Potential |
| Dauphin County | Zone 1 | Highest Potential |
| Delaware County | Zone 1 | Highest Potential |
| Franklin County | Zone 1 | Highest Potential |
| Fulton County | Zone 1 | Highest Potential |
| Huntingdon County | Zone 1 | Highest Potential |
| Indiana County | Zone 1 | Highest Potential |
| Juniata County | Zone 1 | Highest Potential |
| Lackawanna County | Zone 1 | Highest Potential |
| Lancaster County | Zone 1 | Highest Potential |
| Lebanon County | Zone 1 | Highest Potential |
| Lehigh County | Zone 1 | Highest Potential |
| Luzerne County | Zone 1 | Highest Potential |
| Lycoming County | Zone 1 | Highest Potential |
| Mifflin County | Zone 1 | Highest Potential |
| Monroe County | Zone 1 | Highest Potential |
| Montgomery County | Zone 1 | Highest Potential |
| Montour County | Zone 1 | Highest Potential |
| Northampton County | Zone 1 | Highest Potential |
| Northumberland County | Zone 1 | Highest Potential |
| Perry County | Zone 1 | Highest Potential |
| Schuylkill County | Zone 1 | Highest Potential |
| Snyder County | Zone 1 | Highest Potential |
| Sullivan County | Zone 1 | Highest Potential |
| Susquehanna County | Zone 1 | Highest Potential |
| Tioga County | Zone 1 | Highest Potential |
| Union County | Zone 1 | Highest Potential |
| Venango County | Zone 1 | Highest Potential |
| Westmoreland County | Zone 1 | Highest Potential |
| Wyoming County | Zone 1 | Highest Potential |
| York County | Zone 1 | Highest Potential |
Rhode Island
2 of 5 counties (40%) are Zone 1.
| County | Zone | Risk Level |
|---|---|---|
| Kent County | Zone 1 | Highest Potential |
| Washington County | Zone 1 | Highest Potential |
South Carolina
1 of 46 counties (2%) are Zone 1.
| County | Zone | Risk Level |
|---|---|---|
| Greenville County | Zone 1 | Highest Potential |
South Dakota
48 of 66 counties (73%) are Zone 1.
| County | Zone | Risk Level |
|---|---|---|
| Aurora County | Zone 1 | Highest Potential |
| Beadle County | Zone 1 | Highest Potential |
| Bon Homme County | Zone 1 | Highest Potential |
| Brookings County | Zone 1 | Highest Potential |
| Brown County | Zone 1 | Highest Potential |
| Brule County | Zone 1 | Highest Potential |
| Buffalo County | Zone 1 | Highest Potential |
| Campbell County | Zone 1 | Highest Potential |
| Charles Mix County | Zone 1 | Highest Potential |
| Clark County | Zone 1 | Highest Potential |
| Clay County | Zone 1 | Highest Potential |
| Codington County | Zone 1 | Highest Potential |
| Corson County | Zone 1 | Highest Potential |
| Davison County | Zone 1 | Highest Potential |
| Day County | Zone 1 | Highest Potential |
| Deuel County | Zone 1 | Highest Potential |
| Douglas County | Zone 1 | Highest Potential |
| Edmunds County | Zone 1 | Highest Potential |
| Faulk County | Zone 1 | Highest Potential |
| Grant County | Zone 1 | Highest Potential |
| Hamlin County | Zone 1 | Highest Potential |
| Hand County | Zone 1 | Highest Potential |
| Hanson County | Zone 1 | Highest Potential |
| Hughes County | Zone 1 | Highest Potential |
| Hutchinson County | Zone 1 | Highest Potential |
| Hyde County | Zone 1 | Highest Potential |
| Jerauld County | Zone 1 | Highest Potential |
| Kingsbury County | Zone 1 | Highest Potential |
| Lake County | Zone 1 | Highest Potential |
| Lincoln County | Zone 1 | Highest Potential |
| Lyman County | Zone 1 | Highest Potential |
| McCook County | Zone 1 | Highest Potential |
| McPherson County | Zone 1 | Highest Potential |
| Marshall County | Zone 1 | Highest Potential |
| Miner County | Zone 1 | Highest Potential |
| Minnehaha County | Zone 1 | Highest Potential |
| Moody County | Zone 1 | Highest Potential |
| Perkins County | Zone 1 | Highest Potential |
| Potter County | Zone 1 | Highest Potential |
| Roberts County | Zone 1 | Highest Potential |
| Sanborn County | Zone 1 | Highest Potential |
| Spink County | Zone 1 | Highest Potential |
| Stanley County | Zone 1 | Highest Potential |
| Sully County | Zone 1 | Highest Potential |
| Turner County | Zone 1 | Highest Potential |
| Union County | Zone 1 | Highest Potential |
| Walworth County | Zone 1 | Highest Potential |
| Yankton County | Zone 1 | Highest Potential |
Tennessee
39 of 95 counties (41%) are Zone 1.
| County | Zone | Risk Level |
|---|---|---|
| Anderson County | Zone 1 | Highest Potential |
| Bedford County | Zone 1 | Highest Potential |
| Blount County | Zone 1 | Highest Potential |
| Bradley County | Zone 1 | Highest Potential |
| Claiborne County | Zone 1 | Highest Potential |
| Davidson County | Zone 1 | Highest Potential |
| Giles County | Zone 1 | Highest Potential |
| Grainger County | Zone 1 | Highest Potential |
| Greene County | Zone 1 | Highest Potential |
| Hamblen County | Zone 1 | Highest Potential |
| Hancock County | Zone 1 | Highest Potential |
| Hawkins County | Zone 1 | Highest Potential |
| Hickman County | Zone 1 | Highest Potential |
| Humphreys County | Zone 1 | Highest Potential |
| Jackson County | Zone 1 | Highest Potential |
| Jefferson County | Zone 1 | Highest Potential |
| Knox County | Zone 1 | Highest Potential |
| Lawrence County | Zone 1 | Highest Potential |
| Lewis County | Zone 1 | Highest Potential |
| Lincoln County | Zone 1 | Highest Potential |
| Loudon County | Zone 1 | Highest Potential |
| McMinn County | Zone 1 | Highest Potential |
| Macon County | Zone 1 | Highest Potential |
| Madison County | Zone 1 | Highest Potential |
| Marshall County | Zone 1 | Highest Potential |
| Meigs County | Zone 1 | Highest Potential |
| Monroe County | Zone 1 | Highest Potential |
| Moore County | Zone 1 | Highest Potential |
| Perry County | Zone 1 | Highest Potential |
| Roane County | Zone 1 | Highest Potential |
| Rutherford County | Zone 1 | Highest Potential |
| Smith County | Zone 1 | Highest Potential |
| Sullivan County | Zone 1 | Highest Potential |
| Trousdale County | Zone 1 | Highest Potential |
| Union County | Zone 1 | Highest Potential |
| Washington County | Zone 1 | Highest Potential |
| Wayne County | Zone 1 | Highest Potential |
| Williamson County | Zone 1 | Highest Potential |
| Wilson County | Zone 1 | Highest Potential |
Utah
7 of 29 counties (24%) are Zone 1.
| County | Zone | Risk Level |
|---|---|---|
| Carbon County | Zone 1 | Highest Potential |
| Duchesne County | Zone 1 | Highest Potential |
| Grand County | Zone 1 | Highest Potential |
| Piute County | Zone 1 | Highest Potential |
| Sanpete County | Zone 1 | Highest Potential |
| Sevier County | Zone 1 | Highest Potential |
| Uintah County | Zone 1 | Highest Potential |
Virginia
64 of 136 counties (47%) are Zone 1.
| County | Zone | Risk Level |
|---|---|---|
| Alleghany County | Zone 1 | Highest Potential |
| Amelia County | Zone 1 | Highest Potential |
| Appomattox County | Zone 1 | Highest Potential |
| Augusta County | Zone 1 | Highest Potential |
| Bath County | Zone 1 | Highest Potential |
| Bland County | Zone 1 | Highest Potential |
| Botetourt County | Zone 1 | Highest Potential |
| Brunswick County | Zone 1 | Highest Potential |
| Buckingham County | Zone 1 | Highest Potential |
| Campbell County | Zone 1 | Highest Potential |
| Chesterfield County | Zone 1 | Highest Potential |
| Clarke County | Zone 1 | Highest Potential |
| Craig County | Zone 1 | Highest Potential |
| Cumberland County | Zone 1 | Highest Potential |
| Dinwiddie County | Zone 1 | Highest Potential |
| Fairfax County | Zone 1 | Highest Potential |
| Fluvanna County | Zone 1 | Highest Potential |
| Frederick County | Zone 1 | Highest Potential |
| Giles County | Zone 1 | Highest Potential |
| Goochland County | Zone 1 | Highest Potential |
| Henry County | Zone 1 | Highest Potential |
| Highland County | Zone 1 | Highest Potential |
| Lee County | Zone 1 | Highest Potential |
| Louisa County | Zone 1 | Highest Potential |
| Montgomery County | Zone 1 | Highest Potential |
| Nottoway County | Zone 1 | Highest Potential |
| Orange County | Zone 1 | Highest Potential |
| Page County | Zone 1 | Highest Potential |
| Patrick County | Zone 1 | Highest Potential |
| Pittsylvania County | Zone 1 | Highest Potential |
| Powhatan County | Zone 1 | Highest Potential |
| Pulaski County | Zone 1 | Highest Potential |
| Roanoke County | Zone 1 | Highest Potential |
| Rockbridge County | Zone 1 | Highest Potential |
| Rockingham County | Zone 1 | Highest Potential |
| Russell County | Zone 1 | Highest Potential |
| Scott County | Zone 1 | Highest Potential |
| Shenandoah County | Zone 1 | Highest Potential |
| Smyth County | Zone 1 | Highest Potential |
| Spotsylvania County | Zone 1 | Highest Potential |
| Stafford County | Zone 1 | Highest Potential |
| Tazewell County | Zone 1 | Highest Potential |
| Warren County | Zone 1 | Highest Potential |
| Washington County | Zone 1 | Highest Potential |
| Wythe County | Zone 1 | Highest Potential |
| Bedford City | Zone 1 | Highest Potential |
| Bristol City | Zone 1 | Highest Potential |
| Buena Vista City | Zone 1 | Highest Potential |
| Clifton Forge City | Zone 1 | Highest Potential |
| Covington City | Zone 1 | Highest Potential |
| Danville City | Zone 1 | Highest Potential |
| Fairfax City | Zone 1 | Highest Potential |
| Falls Church City | Zone 1 | Highest Potential |
| Harrisonburg City | Zone 1 | Highest Potential |
| Lexington City | Zone 1 | Highest Potential |
| Manassas City | Zone 1 | Highest Potential |
| Manassas Park City | Zone 1 | Highest Potential |
| Petersburg City | Zone 1 | Highest Potential |
| Radford City | Zone 1 | Highest Potential |
| Roanoke City | Zone 1 | Highest Potential |
| Salem City | Zone 1 | Highest Potential |
| Staunton City | Zone 1 | Highest Potential |
| Waynesboro City | Zone 1 | Highest Potential |
| Winchester City | Zone 1 | Highest Potential |
Washington
7 of 39 counties (18%) are Zone 1.
| County | Zone | Risk Level |
|---|---|---|
| Clark County | Zone 1 | Highest Potential |
| Ferry County | Zone 1 | Highest Potential |
| Okanogan County | Zone 1 | Highest Potential |
| Pend Oreille County | Zone 1 | Highest Potential |
| Skamania County | Zone 1 | Highest Potential |
| Spokane County | Zone 1 | Highest Potential |
| Stevens County | Zone 1 | Highest Potential |
Wisconsin
28 of 72 counties (39%) are Zone 1.
| County | Zone | Risk Level |
|---|---|---|
| Buffalo County | Zone 1 | Highest Potential |
| Crawford County | Zone 1 | Highest Potential |
| Dane County | Zone 1 | Highest Potential |
| Dodge County | Zone 1 | Highest Potential |
| Door County | Zone 1 | Highest Potential |
| Fond du Lac County | Zone 1 | Highest Potential |
| Grant County | Zone 1 | Highest Potential |
| Green County | Zone 1 | Highest Potential |
| Green Lake County | Zone 1 | Highest Potential |
| Iowa County | Zone 1 | Highest Potential |
| Jefferson County | Zone 1 | Highest Potential |
| Lafayette County | Zone 1 | Highest Potential |
| Langlade County | Zone 1 | Highest Potential |
| Marathon County | Zone 1 | Highest Potential |
| Menominee County | Zone 1 | Highest Potential |
| Pepin County | Zone 1 | Highest Potential |
| Pierce County | Zone 1 | Highest Potential |
| Portage County | Zone 1 | Highest Potential |
| Richland County | Zone 1 | Highest Potential |
| Rock County | Zone 1 | Highest Potential |
| St. Croix County | Zone 1 | Highest Potential |
| Shawano County | Zone 1 | Highest Potential |
| Vernon County | Zone 1 | Highest Potential |
| Walworth County | Zone 1 | Highest Potential |
| Washington County | Zone 1 | Highest Potential |
| Waukesha County | Zone 1 | Highest Potential |
| Waupaca County | Zone 1 | Highest Potential |
| Wood County | Zone 1 | Highest Potential |
West Virginia
20 of 55 counties (36%) are Zone 1.
| County | Zone | Risk Level |
|---|---|---|
| Berkeley County | Zone 1 | Highest Potential |
| Brooke County | Zone 1 | Highest Potential |
| Grant County | Zone 1 | Highest Potential |
| Greenbrier County | Zone 1 | Highest Potential |
| Hampshire County | Zone 1 | Highest Potential |
| Hancock County | Zone 1 | Highest Potential |
| Hardy County | Zone 1 | Highest Potential |
| Jefferson County | Zone 1 | Highest Potential |
| Marshall County | Zone 1 | Highest Potential |
| Mercer County | Zone 1 | Highest Potential |
| Mineral County | Zone 1 | Highest Potential |
| Monongalia County | Zone 1 | Highest Potential |
| Monroe County | Zone 1 | Highest Potential |
| Morgan County | Zone 1 | Highest Potential |
| Ohio County | Zone 1 | Highest Potential |
| Pendleton County | Zone 1 | Highest Potential |
| Pocahontas County | Zone 1 | Highest Potential |
| Preston County | Zone 1 | Highest Potential |
| Summers County | Zone 1 | Highest Potential |
| Wetzel County | Zone 1 | Highest Potential |
Wyoming
21 of 23 counties (91%) are Zone 1.
| County | Zone | Risk Level |
|---|---|---|
| Albany County | Zone 1 | Highest Potential |
| Big Horn County | Zone 1 | Highest Potential |
| Campbell County | Zone 1 | Highest Potential |
| Carbon County | Zone 1 | Highest Potential |
| Converse County | Zone 1 | Highest Potential |
| Crook County | Zone 1 | Highest Potential |
| Fremont County | Zone 1 | Highest Potential |
| Goshen County | Zone 1 | Highest Potential |
| Hot Springs County | Zone 1 | Highest Potential |
| Johnson County | Zone 1 | Highest Potential |
| Laramie County | Zone 1 | Highest Potential |
| Lincoln County | Zone 1 | Highest Potential |
| Natrona County | Zone 1 | Highest Potential |
| Niobrara County | Zone 1 | Highest Potential |
| Park County | Zone 1 | Highest Potential |
| Sheridan County | Zone 1 | Highest Potential |
| Sublette County | Zone 1 | Highest Potential |
| Sweetwater County | Zone 1 | Highest Potential |
| Teton County | Zone 1 | Highest Potential |
| Uinta County | Zone 1 | Highest Potential |
| Washakie County | Zone 1 | Highest Potential |