Region
Colorado
20
United States
16
Wyoming
12
Massachusetts
11
Illinois
10
Arizona
8
Kansas
8
Mississippi River
8
Montana
8
California
7
Georgia
7
Maine
7
New Mexico
7
Tennessee
7
Indiana
6
Iowa
6
New York (State)
6
Ohio
6
Oklahoma
6
Texas
6
Washington (State)
6
Louisiana
5
North Carolina
5
Utah
5
West Virginia
5
Florida
4
Hawaii
4
Maryland
4
Wisconsin
4
Connecticut
3
Idaho
3
Kentucky
3
Maricopa County
3
Middle West
3
Missouri
3
New Jersey
3
Pennsylvania
3
Virginia
3
Alabama
2
Alaska
2
Appalachian Region
2
Arkansas
2
Colorado River (Colo.-Mexico)
2
Columbia River
2
Delaware
2
Flint River
2
Glen Canyon Dam
2
Grand Canyon
2
Hawaii Island
2
Ipswich River Watershed
2
more ...