Region
United States
91
California
41
Oregon
37
Alaska
31
New Mexico
20
Colorado
19
Utah
15
Florida
14
Montana
14
Nevada
14
Washington (State)
14
Wyoming
14
Arizona
13
Texas
13
Idaho
12
Kentucky
10
North America
10
Minnesota
9
Hawaii
8
New York (State)
8
Pennsylvania
8
Great Lakes (North America)
7
Louisiana
7
Southern States
7
Massachusetts
6
Upper Klamath Lake
6
Arkansas
5
Maine
5
North Dakota
5
Ohio
5
Paradox Formation
5
South Carolina
5
Columbia Plateau
4
Idaho National Laboratory Region
4
Kansas
4
New Jersey
4
North Carolina
4
South Dakota
4
West (U.S.)
4
Yellowstone National Park
4
Alabama
3
Atlantic Coast (U.S.)
3
Belize
3
Black Hills (S.D. and Wyo.)
3
Carrie Bow Cay
3
Everglades National Park
3
Illinois
3
Indiana
3
Iowa
3
Maryland
3
more ...