Region
Abbotsford Region
1
Aberdeen Proving Ground
12
Aberdeen Proving Ground (Md.)
4
Aberdeen Region
1
Abert Rim Wilderness (Or.)
1
Abert, Lake
1
Abraham Lincoln National Heritage Area (Ill.)
1
Absaroka-Beartooth Wilderness (Mont. and Wyo.)
1
Acadia National Park
2
Acadia National Park (Me.)
6
Accomack County
1
Acoma
2
Ada County
1
Adak Island
3
Adak Island (Alaska)
1
Adams County
14
Adams National Historical Park (Quincy, Mass.)
1
Addison County
1
Aden, Gulf of
1
Adirondack Mountains
1
Adirondack Mountains Region
2
Admiralty Island
1
Admiralty Island National Monument Wilderness (Alaska)
6
Adriatic Sea
1
Adriatic Sea Region
1
Afghanistan
215
Afognak Region
1
Africa
135
Africa South of the Sahara
36
Africa, Central
5
Africa, East
2
Africa, Eastern
1
Africa, French-speaking Equatorial
1
Africa, French-speaking West
1
Africa, North
6
Africa, Northeast
6
Africa, Northwest
1
Africa, Southern
7
Africa, Sub-Saharan
52
Africa, West
6
Africa, Western
3
Agate Fossil Beds National Monument (Neb.)
1
Agua Caliente Band of Cahuilla Indians of the Agua Caliente Indian Reservation, California
2
Agua Caliente Indian Reservation (Calif.)
1
Ah Pah Creek
1
Ah Pah Creek Watershed (Calif.)
2
Aiken Region
1
Ak Chin Reservation (Ariz.)
2
Ak-Chin Indian Community
1
Al Lith Region
2
more ...