Region
Abbotsford
1
Aberdeen Proving Ground
3
Abū Ẓaby (United Arab Emirates)
1
Accomack County
1
Adirondack Mountains
1
Afghanistan
5
Africa
1
Africa, West
2
Alabama
16
Alafia River
1
Alameda County
1
Alamosa River Watershed
1
Alaska
41
Alaska Maritime National Wildlife Refuge (Alaska)
1
Alaska, Gulf of
1
Albany
2
Albany Region
1
Alberta
3
Alberta, Northern
1
Albuquerque
2
Algeria
1
Alps
1
Amelia
1
American Samoa
1
Anacostia River (Md. and Washington, D.C.)
2
Anchorage
1
Anhui Sheng
1
Animas River (Colo. and N.M.)
4
Animas River Watershed
1
Animas River Watershed (Colo. and N.M.)
6
Antarctica
8
Apache County
1
Apalachicola River
1
Appalachian Region
10
Aral Sea (Uzbekistan and Kazakhstan)
1
Arapahoe County
1
Arctic Ocean
2
Arctic Regions
1
Arctic regions
14
Ardmore
1
Arecibo
1
Argentina
1
Arizona
15
Arkansas
3
Arkansas City
1
Arkansas River
1
Arkansas River Valley
1
Arkansas River Watershed
1
Arnold Air Force Base
1
Arnold Air Force Base Region
1
more ...