Region
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Anacostia River (Md. and Washington, D.C.)
1
Anaktuvuk Pass
1
Anaktuvuk Pass (Alaska)
1
Andes
2
Animas River Watershed (Colo. and N.M.)
2
Ann Arbor
3
Annapolis
1
Anne Arundel County
1
Antarctica
1
Antelope House Site (Ariz.)
1
Antelope Mesa (Ariz.)
1
Antietam National Battlefield
2
Antietam National Battlefield (Md.)
6
Apopka, Lake, Watershed
1
Appalachian Basin
1
Appalachian Mountains
1
Appalachian Region
21
Appalachian Region, Southern
5
Appomattox Court House National Historical Park (Va.)
1
Arab countries
1
Aravaipa Canyon
1
Aravaipa Canyon (Ariz.)
1
Arcata
1
Archuleta County
1
Archuleta County (Colo.)
1
Arctic regions
8
Argentina
2
Argonne
3
Arizona
120
Arkansas
29
Arkansas River Watershed
1
Arlington
1
Arlington County
1
Aroostook County
1
Aroostook-Prestile Basins
1
Ascensión (Chihuahua)
2
Ashtabula
1
Asia
12
Asia, Central
1
Asia, Eastern
3
Aspen Shelter Site (Utah)
1
Assateague Island (Md. and Va.)
1
Atlanta
13
Atlanta (Ga.)
2
Atlantic Coast (Middle Atlantic States)
3
Atlantic Coast (New England)
1
Atlantic Coast (North America)
1
Atlantic Coast (U.S.)
6
Atlantic Ocean
1
Atlantic Ocean Region
1
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