Region
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Apalachicola River Watershed
5
Appalachian Region
12
Apple Valley
1
Arab countries
2
Arabian Peninsula
1
Aral Sea Watershed (Uzbekistan and Kazakhstan)
1
Arapahoe County
1
Arches National Park (Utah)
1
Arctic Archipelago
2
Arctic Archipelago (Nunavut and N.W.T.)
2
Arctic Ocean
2
Arctic Regions
1
Arctic regions
10
Ardmore
1
Arecibo
1
Argentina
6
Arid regions
1
Arikaree Aquifer
1
Arikaree Formation
1
Arizona
196
Arkansas
65
Arkansas City
1
Arkansas River
8
Arkansas River Valley
4
Arkansas River Watershed
8
Arlington
1
Arno River
1
Arnold Air Force Base
3
Arnold Air Force Base Region
1
Arrow Lakes region
1
Arthur R. Marshall Loxahatchee National Wildlife Refuge
1
Arvada
1
Ashland
1
Ashland Region
1
Ashley River
1
Ashtabula County
1
Asia
20
Asia, Central
11
Assabet River
2
Assateague Island (Md. and Va.)
1
Assiniboine and Sioux Tribes of the Fort Peck Indian Reservation, Montana
2
Assumption Parish
1
Assyria
1
Astrop
1
Atascosa County
1
Atatürk Dam (Turkey)
1
Atchafalaya River
2
Atchafalaya River Watershed
2
Athabasca River
1
Athabasca River Watershed
1
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