- Above Stanford University stock-farm1
- Above mine adit, Mahoney Creek, George Inlet, Revillaglgedo Island1
- Acadia National Park, Mount Desert Island, Sieur de Mont at base of Dorr Mountain1
- Acadia National Park, Upper Hadlock Pond1
- Accomack1
- Across main channel of Mississippi River, 1/4 mile north of Red Wing, Minnesota. T24N R18W S151
- Adair1
- Adair Creek1
- Adak Island6
- Adak Island, Central Aleutian Islands, Finger Bay1
- Adak Island, Clam Lagoon1
- Adak Island, above creek near Shagak Bay1
- Adak Island, on slopes of Mt. Moffet1
- Adak Island, slopes along Mitt Creek, Upper end of Sweeper Cove1
- Adak Island, west side of Andrew Lake1
- Adak Island; stream two miles east of Shagack Bay1
- Adams3
- Adirondack Mountains1
- Adirondack Mountains, along Kempshall Mountain Trail, 6 miles northeast of Long Lake Village1
- Adirondack Mountains, bank of Raquette River below Buttermilk Falls, 5 miles southwest of Long Lake Village1