Region
United States
71
Colorado
56
California
21
Washington (D.C.)
21
Utah
16
West (U.S.)
15
Rocky Mountains
14
Great Britain
12
Southwest, New
12
Mexico
11
New Mexico
11
Colorado Plateau
10
Galapagos Islands
10
Yellowstone National Park
10
Alaska
9
Arctic regions
9
North America
9
Northwest Passage
9
Arizona
7
Australia
7
Massachusetts
7
White Sands National Monument
7
White Sands National Park (N.M.)
7
Africa
5
Germany
5
Great Basin
5
Hawaii
5
Nebraska
5
Tularosa Valley (N.M. and Tex.)
5
Walden Woods
5
America
4
Baja California (Mexico : Peninsula)
4
Colorado River (Colo.-Mexico)
4
Costa Rica
4
England
4
Florida
4
Grand Canyon
4
Japan
4
Latin America
4
New York (State)
4
Rocky Mountain National Park (Colo.)
4
South America
4
South Dakota
4
Walden Woods (Mass.)
4
Washington (State)
4
Wyoming
4
Amazon River Valley
3
Arches National Park (Utah)
3
Baja California (Peninsula)
3
Central America
3
more ...