Region
United States
228
Mexico, Gulf of
50
Texas
34
Missouri River Watershed
33
Colorado River Watershed (Colo.-Mexico)
31
Mississippi River Watershed
16
Ohio River Watershed
13
Northeastern States
8
California
7
Pacific Coast
7
Western Gulf of Mexico basins
7
Columbia River Watershed
6
Atlantic States
5
Saint Lawrence River Watershed
5
Hudson Bay
4
Great Basin
3
Middle West
3
Southern States
3
Washington (State)
3
Cumberland River Watershed (Ky. and Tenn.)
2
Hudson Bay Watershed
2
Oregon
2
Tennessee River Watershed
2
West (U.S.)
2
Europe
1
Hawaii
1
Hudson River (N.Y. and N.J.)
1
Lower Atlantic slope
1
Mexico, Gulf of, Watershed
1
New York (State)
1
Pacific slope basins
1
Snake River Watershed (Wyo.-Wash.)
1
Southwest, New
1