Region
San Juan Basin (N.M. and Colo.)
10
Kentucky
9
Ozark Mountains Region
7
Colorado
5
Kansas
5
Massachusetts
5
Southwest, New
5
Arizona
4
New Mexico
4
Wyoming
4
Maine
3
Texas
3
Utah
3
California
2
Colorado River Watershed (Colo.-Mexico)
2
Great Plains
2
Mississippian Plateau
2
Missouri
2
Nevada
2
North Carolina
2
Oklahoma
2
Washington County
2
Appalachian Region
1
Boston
1
Boyd County
1
Breathitt County
1
Cape Cod
1
Cape Hatteras National Seashore
1
Cape Hatteras National Seashore (N.C.)
1
Carbon County
1
Carter County
1
Central Oklahoma Aquifer (Okla.)
1
Charles River Watershed
1
Cimarron County
1
Cimarron County (Okla.)
1
Cochise County
1
Colorado River Region (Colo.-Mexico)
1
Cumberland County
1
Dakota Formation
1
Denver Basin
1
Denver Region
1
Elliott County
1
Floyd County
1
Franklin area
1
Fremont County
1
Fruitland Formation (Colo. and N.M.)
1
Gove County
1
Graham County
1
Gray County
1
Great Basin
1
more ...