Region
California
17
Nevada
12
Alaska
8
Arizona
4
Colorado
4
Oregon
4
Washington (State)
4
Idaho
3
Montana
3
Northwest, Pacific
3
Utah
3
West (U.S.)
3
Mississippi River Valley
2
San Joaquin Valley
2
Santa Maria Basin
2
United States
2
Yucca Mountain Region
2
Ajo Region
1
Alameda County
1
Arkansas
1
Barstow Region
1
Blackfoot Region
1
Bonneville, Lake
1
California, Northern
1
Cascade Range
1
Chihuahua (State)
1
Feather River Region
1
Fish Lake Region
1
Fish Lake Valley
1
Fisher Valley
1
Flagstaff Region
1
Fox Mountain (Nye County)
1
Franciscan Complex (Calif.)
1
Fresno County
1
Grant County
1
Great Basin
1
Gulf Coast (U.S.)
1
Harney County
1
Hawaii
1
Honcut Creek Region
1
Hopewell Region
1
Horry County
1
Las Vegas Valley
1
Madison Range
1
Martha's Vineyard
1
Massachusetts
1
Merced River Valley
1
Mexico
1
Mid-Atlantic Bight
1
Middle Atlantic States
1
more ...