Spatial Coverage
- Piceance Creek Basin1
- Piceance Creek Basin.1
- Pocono Mountains (Pa.)1
- Pocono Mountains.1
- Pony Express National Historic Trail1
- Portage River (Ohio)1
- Portage River.1
- Québec1
- Québec Campaign, Québec, 17591
- Québec.1
- Railroads1
- Rapidan River (Va.)1
- Rapidan River.1
- Red River Watershed (Tex.-La.)1
- Red River Watershed.1
- Republican River Watershed (Neb. and Kan.)1
- Republican River Watershed.1
- Rhode Island.1
- Richmond (Va.)1
- Rock Island1
