Region
United States
22
California
13
Arkansas
11
Nevada
9
Florida
8
Mississippi River
7
Snake River Plain (Idaho and Or.)
7
Mississippi River Valley
6
Snake River Plain
6
Tennessee
6
Texas
6
Washington (State)
6
Arizona
5
Great Lakes (North America)
5
Indiana
5
Louisiana
5
Maryland
5
Mississippi
5
Missouri
5
Atlantic Coast (U.S.)
4
High Plains Aquifer
4
Minnesota
4
New Jersey
4
Oregon
4
Yucca Mountain
4
Atlantic Coast
3
Colorado
3
Galveston Region
3
Georgia
3
Houston Region
3
Millington Region
3
New Mexico
3
North Dakota
3
Rhode Island
3
Santa Barbara County
3
Venice (Italy)
3
Alaska
2
Colorado River (Colo.-Mexico)
2
Columbia River Watershed
2
Devils Hole
2
Devils Lake Watershed
2
Erie, Lake
2
Everglades
2
Everglades (Fla.)
2
Florida, South
2
Glynn County
2
Great Lakes Region (North America)
2
Hawaii
2
High Plains (U.S.)
2
Illinois
2
more ...