Region
United States
173
Alaska
30
Arctic National Wildlife Refuge
26
Arctic National Wildlife Refuge (Alaska)
21
Great Britain
14
California
12
Germany
9
West (U.S.)
9
Australia
8
Yellowstone National Park
8
Yosemite National Park (Calif.)
8
Africa
7
Arizona
6
New York (State)
6
South Africa
6
Colorado
5
Texas
5
China
4
Ecuador
4
Europe
4
Grand Canyon National Park (Ariz.)
4
Grand Teton National Park (Wyo.)
4
Great Smoky Mountains National Park (N.C. and Tenn.)
4
Iowa
4
Montana
4
Oregon
4
Colombia
3
Costa Rica
3
Deer Flat National Wildlife Refuge (Idaho and Or.)
3
Dinosaur National Monument (Colo. and Utah)
3
Echo Park Dam (Colo.)
3
Florida
3
Hells Canyon (Idaho and Or.)
3
Idaho
3
Illinois
3
Mexico
3
Namibia
3
New Jersey
3
North America
3
North Slope
3
Ontario
3
Rocky Flats National Wildlife Refuge
3
Rocky Flats National Wildlife Refuge (Colo.)
3
Snake River (Wyo.-Wash.)
3
South Carolina
3
Switzerland
3
Tanzania
3
Tropics
3
Virginia
3
Wyoming
3
more ...