Region
United States
506
Northwest, Pacific
25
California
23
Australia
14
Africa
13
West (U.S.)
12
Washington (State)
10
North America
9
Texas
9
New Mexico
8
Florida
7
Hawaii
7
Southern States
7
Alaska
6
Monterey Bay National Marine Sanctuary (Calif.)
6
Pacific Area
6
Arizona
5
Nebraska
5
Oregon
5
Utah
5
Wyoming
5
Colorado River Watershed (Colo.-Mexico)
4
Columbia River
4
Great Britain
4
Ireland
4
Mexico
4
Platte River Watershed
4
Russia (Federation)
4
South Platte River Watershed (Colo. and Neb.)
4
Tellico Dam (Tenn.)
4
Tennessee
4
Washington County
4
Alabama
3
American Samoa
3
Asia
3
Columbia River Watershed
3
Great Lakes Region (North America)
3
Idaho
3
India
3
Maine
3
Mojave Desert
3
North Carolina
3
North Pacific Ocean
3
Peru
3
Platte River Watershed (Neb.)
3
Russian Far East
3
San Juan River Watershed (Colo.-Utah)
3
Southwestern States
3
Yellowstone National Park
3
Arkansas
2
more ...