National Exposure Index: 3221 US Counties Ranked

Every US county scored on radon potential, pre-1980 (lead-paint-era) housing, air quality, Superfund proximity, and industrial chemical releases – 3221 counties ranked using 2023 federal data. Browse by state, or see the most-exposed counties nationally.

Quick Answer

This index links to 82 pages organized into 2 categories for easy browsing.

Most exposed counties (national top 30)

Allegheny County (#1) National exposure rank 1 of 3221
Shoshone County (#2) National exposure rank 2 of 3221
Hamilton County (#3) National exposure rank 3 of 3221
Montgomery County (#4) National exposure rank 4 of 3221
Cass County (#5) National exposure rank 5 of 3221
Stark County (#6) National exposure rank 6 of 3221
Marion County (#7) National exposure rank 7 of 3221
Silver Bow County (#8) National exposure rank 8 of 3221
Berks County (#9) National exposure rank 9 of 3221
Calhoun County (#10) National exposure rank 10 of 3221
Jefferson County (#11) National exposure rank 11 of 3221
Jefferson County (#12) National exposure rank 12 of 3221
Macon County (#13) National exposure rank 13 of 3221
Clinton County (#14) National exposure rank 14 of 3221
Delaware County (#15) National exposure rank 15 of 3221
Marion County (#16) National exposure rank 16 of 3221
Tuscarawas County (#17) National exposure rank 17 of 3221
Vermilion County (#18) National exposure rank 18 of 3221
Westmoreland County (#19) National exposure rank 19 of 3221
Beaver County (#20) National exposure rank 20 of 3221
Lehigh County (#21) National exposure rank 21 of 3221
Marshall County (#22) National exposure rank 22 of 3221
Schuylkill County (#23) National exposure rank 23 of 3221
St. Joseph County (#24) National exposure rank 24 of 3221
Wyandotte County (#25) National exposure rank 25 of 3221
Allen County (#26) National exposure rank 26 of 3221
Branch County (#27) National exposure rank 27 of 3221
Elkhart County (#28) National exposure rank 28 of 3221
Jackson County (#29) National exposure rank 29 of 3221
LaSalle County (#30) National exposure rank 30 of 3221

Browse by state (52)

Alabama 67 ranked counties
Alaska 30 ranked counties
Arizona 15 ranked counties
Arkansas 75 ranked counties
California 58 ranked counties
Colorado 64 ranked counties
Connecticut 8 ranked counties
Delaware 3 ranked counties
District of Columbia 1 ranked county
Florida 67 ranked counties
Georgia 159 ranked counties
Hawaii 5 ranked counties
Idaho 44 ranked counties
Illinois 102 ranked counties
Indiana 92 ranked counties
Iowa 99 ranked counties
Kansas 105 ranked counties
Kentucky 120 ranked counties
Louisiana 64 ranked counties
Maine 16 ranked counties
Maryland 24 ranked counties
Massachusetts 14 ranked counties
Michigan 83 ranked counties
Minnesota 87 ranked counties
Mississippi 82 ranked counties
Missouri 115 ranked counties
Montana 56 ranked counties
Nebraska 93 ranked counties
Nevada 17 ranked counties
New Hampshire 10 ranked counties
New Jersey 21 ranked counties
New Mexico 33 ranked counties
New York 62 ranked counties
North Carolina 100 ranked counties
North Dakota 53 ranked counties
Ohio 88 ranked counties
Oklahoma 77 ranked counties
Oregon 36 ranked counties
Pennsylvania 67 ranked counties
Puerto Rico 78 ranked counties
Rhode Island 5 ranked counties
South Carolina 46 ranked counties
South Dakota 66 ranked counties
Tennessee 95 ranked counties
Texas 254 ranked counties
Utah 29 ranked counties
Vermont 14 ranked counties
Virginia 133 ranked counties
Washington 39 ranked counties
West Virginia 55 ranked counties
Wisconsin 72 ranked counties
Wyoming 23 ranked counties