Subject
- Boundaries9
- Administrative and political divisions4
- Protected areas3
- States3
- Wilderness areas3
- Biology and Ecology2
- Counties2
- Environment2
- Inland Waters2
- Society2
- Wilderness area monitoring2
- Battlefields1
- Farming1
- Forest reserves1
- Historic parks1
- Historic sites1
- Indian reservations1
- Military1
- Military parks1
- National parks and reserves1