Region
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American Memorial Park (Northern Mariana Islands)
1
American Samoa
10
Anchorage
1
Anchorage Region
6
Androscoggin River Watershed (N.H. and Me.)
1
Annapolis Region
3
Anne Arundel County
2
Antelope Valley
3
Antelope Valley Region
1
Antioch
1
Antioch Region
1
Antofagasta (Region)
2
Apache County
5
Apache County (Ariz.)
1
Apalachicola River Watershed
1
Appalachian Region
2
Appleton Region
1
Aquia Formation
4
Ardmore Quadrangle
1
Arecibo
1
Arikaree Aquifer
3
Arikaree Formation
1
Arizona
167
Arkansas
89
Arkansas River
3
Arkansas River Valley
6
Arkansas River Watershed
5
Armells Creek, East Fork Watershed
1
Arnold Air Force Base
4
Ashford
1
Ashland County
1
Ashland Region
1
Ashtabula County
2
Asia
2
Atascosa County
1
Athens Region
1
Atlantic Coast
3
Atlantic Coast (U.S.)
14
Atlantic County
1
Atlantic Ocean
1
Atlantic States
1
Augusta
1
Aunuu Island
2
Aurora County
2
Austin
2
Austin Region
3
Avoyelles Parish
1
Avra Valley
1
Avra-Altar Valley
1
Avra-Altar Valley (Ariz.)
1
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