Region
Arizona
New Mexico
22
Utah
17
United States
16
Grand Canyon
15
California
12
Grand Canyon (Ariz.)
8
Nevada
8
Colorado
7
Navajo Indian Reservation
7
Cochise County
6
Colorado River (Colo.-Mexico)
6
Gila County
6
Grand Canyon Region
6
Hopi Indian Reservation
6
Southwest, New
6
Yavapai County
5
Grand Canyon National Park
4
Grand Canyon National Park (Ariz.)
4
Mohave County
4
Santa Rita Mountains
4
Tombstone
4
Tombstone (Ariz.)
4
West (U.S.)
4
Wyoming
4
Mexico
3
Santa Cruz County
3
Baboquivari Mountains
2
Black Canyon (Ariz. and Nev.)
2
Black Mesa (Navajo County and Apache County)
2
Bradshaw Mountains
2
Brady Butte Region
2
Central
2
Chinle Formation
2
Flagstaff Region
2
Graham County
2
Grand Canyon Region (Ariz.)
2
Lava Falls Rapids (Ariz.)
2
Mohawk Canyon
2
Montana
2
Mule Mountains
2
Pinal County
2
Poachie Range
2
Roskruge Mountains
2
Sierrita Mountains
2
Sonora (State)
2
Toreva Formation (Ariz.)
2
Ajo Region
1
Alaska
1
Altar Valley
1
more ...