Region
New Mexico
64
Wyoming
47
San Juan County
46
San Juan County (N.M.)
41
Montana
26
Colorado
23
Campbell County
22
Utah
16
Campbell County (Wyo.)
15
Sheridan County
14
Rio Arriba County
13
Rio Arriba County (N.M.)
13
Powder River County
12
Johnson County
10
Johnson County (Wyo.)
10
Sandoval County
10
Sandoval County (N.M.)
10
Powder River County (Mont.)
8
Sheridan County (Wyo.)
7
Big Horn County
6
Illinois
6
Kane County
6
Moffat County
6
Rosebud County
6
Carbon County
5
Emery County
5
Jackson County
5
Rio Blanco County
5
Fort Union Formation
4
Jackson County (Colo.)
4
McKinley County
4
La Plata County
3
McKinley County (N.M.)
3
Powder River Basin (Wyo. and Mont.)
3
Powder River Watershed (Wyo. and Mont.)
3
Rio Blanco County (Colo.)
3
Sweetwater County
3
United States
3
Alaska
2
Grand County
2
Huerfano County
2
Kentucky
2
La Plata County (Colo.)
2
Leslie County
2
Moffat County (Colo.)
2
North Dakota
2
Pennsylvania
2
Perry County
2
Sanpete County
2
Schuylkill County
2
more ...