The National Park Service (NPS) is an agency of the United States federal government that manages all U.S. national parks, many American national monuments, and other conservation and historical properties with various title designations. It was created on August 25, 1916, and the 21,989 employees of the NPS oversee 405 units, of which 59 are designated national parks. The National Park Services will celebrate its centennial in 2016.
Currently, there are 405 park units managed by the NPS. These units are assigned one of the 16 designations: national park, national monument, national preserve, national historic site, national historic park, national memorial, national battlefield, national cemetery, national recreation area, national seashore, national lakeshore, national river, national parkway, national trail, affiliated areas and other designations.