Region
United States
532
Mexico, Gulf of
53
Missouri River Watershed
36
Colorado River Watershed (Colo.-Mexico)
34
Texas
34
Mississippi River Watershed
19
California
16
Ohio River Watershed
13
Pacific Coast
11
Columbia River Watershed
8
Northeastern States
8
Western Gulf of Mexico basins
7
Atlantic States
6
Puerto Rico
6
Saint Lawrence River Watershed
6
Hudson Bay
5
Great Basin
4
United States Virgin Islands
4
Canada
3
Hawaii
3
Middle West
3
Oregon
3
Snake River Watershed (Wyo.-Wash.)
3
Southern States
3
Washington (State)
3
Cumberland River Watershed (Ky. and Tenn.)
2
Hudson Bay Watershed
2
Netherlands
2
Tennessee River Watershed
2
West (U.S.)
2
Arizona
1
Colorado
1
El Niño Current
1
Europe
1
Hudson River (N.Y. and N.J.)
1
Idaho
1
Lower Atlantic slope
1
Mexico, Gulf of, Watershed
1
Missouri
1
New York (State)
1
North America
1
Northwestern States
1
Pacific slope basins
1
Pennsylvania
1
Southwest, New
1
Utah
1
Wyoming
1