Region
United States
29
Colorado
13
Georgia
13
Fort Gordon (Ga.)
11
Aberdeen Proving Ground
6
Maryland
6
Washington (State)
6
Arapahoe County
5
Elbert County
5
New Jersey
5
North Carolina
5
Fort Bragg
4
Arizona
3
California
3
Florida
3
Idaho
3
Kentucky
3
Oklahoma
3
Texas
3
Aberdeen Proving Ground (Md.)
2
Bexar County
2
China
2
Clark County
2
Clark County (Wash.)
2
Denver
2
Douglas County
2
Fort Gordon
2
Great Lakes (North America)
2
Kansas
2
Kansas City
2
Minnesota
2
Missouri
2
Monmouth County
2
Montana
2
Morgan County
2
Ohio
2
Seattle
2
South Carolina
2
South Dakota
2
Ada Aquifer (Okla.)
1
Africa
1
Albany
1
Arkansas
1
Asia
1
Beale Air Force Base
1
Beale Air Force Base (Calif.)
1
Caribbean Area
1
Cherryvale
1
Chicago
1
Clark Fork Watershed (Mont. and Idaho)
1
more ...