National Park Service Sites
As of 2015, the National Park Service counted more than 400 units in the National Park Service System. In total, these 400+ special places were visited by more than 275 million people. Included in this list of special places are National Parks, National Monuments, National Preserves, National Historic Sites, National Military Parks, National Historical Parks, National Battlefield Parks, National Battlefields, National Memorials, National Recreation Areas, National Seashores, National Lakeshores, National Rivers, National Reserves, National Parkways, National Historic & Scenic Trails, National Cemeteries, National Heritage Areas and yet other NPS areas. These properties are spread across 49 states, the District of Columbia, the US Virgin Islands, Puerto Rico and the US Territories of Guam, American Samoa and the Northern Mariana Islands (only Delaware has not a single unit of the National Park Service system).
For folks who are really interested in visiting and learning about our National Parks, check out The National Parks Travelers Club.
National Historical Parks
National Historic Sites
International Historic Site
National Battlefield Parks
National Military Parks
National Battlefield Site
National Recreation Areas
National Heritage Areas
Other NPS Areas
Rocky Mountain National Park, Colorado
Most photos courtesy of TheArmchairExplorer, CCA-by-SA 3.0 License
Some photos courtesy of the National Park Service