Region
Alaska
4
Colorado
4
United States
3
Arizona
2
Louisiana
2
Alberta
1
Barataria-Terrebonne Estuarine Complex
1
Bighorn Basin (Mont. and Wyo.)
1
California
1
Columbia Plateau
1
Delta Junction (Alaska)
1
Denver
1
El Paso County
1
Everglades
1
Florida
1
Great Plains
1
Gunnison Gorge National Conservation Area
1
Mancos Shale
1
Manitoba
1
Missouri
1
Nevada
1
New Orleans
1
North America
1
Piceance Creek Watershed
1
Piceance Creek Watershed (Colo.)
1
San Rafael Valley
1
Santa Cruz Region
1
Seattle
1
Texas
1
Tuba City
1
Washington (State)
1
Washington Region
1
Wind River Basin
1
Wisconsin
1
Wyoming
1
Yucca Mountain
1