Region
Colorado
9
Minnesota
5
Massachusetts
4
Pennsylvania
4
Tioga County
4
Mississippi River Watershed
3
North Carolina
3
Wisconsin
3
Alaska
2
Alaska, Gulf of
2
Colorado River (Colo.-Mexico)
2
Colorado River Watershed (Colo.-Mexico)
2
Cowanesque River (Pa. and N.Y.)
2
Iowa
2
Michigan
2
Michigan, Lake, Watershed
2
Mississippi River
2
Puerto Rico
2
Red River of the North Watershed
2
Susquehanna River Watershed
2
Texas
2
Virginia
2
West Virginia
2
Arizona
1
Arkansas
1
Australia
1
Bering Sea
1
Big Bend National Park
1
Boise River
1
Boise River (Idaho)
1
Buffalo River Region
1
Buffalo River Region (Ark.)
1
Flower Garden Banks National Marine Sanctuary
1
French Polynesia
1
Great Lakes Watershed (North America)
1
Great Smoky Mountains National Park (N.C. and Tenn.)
1
Gunnison River
1
Guánica Bay
1
Heron Island (Qld.)
1
Idaho
1
Illinois
1
Illinois River
1
Indonesia
1
Ipswich River Watershed
1
Kanawha River Watershed (W. Va.)
1
Kansas
1
Lees Ferry
1
Louisiana
1
Maldives
1
Mariana Islands
1
more ...