National Park Service
The National Park Service is the a government agency in the United States that deals with national parks and monuments. It is a branch of the United States Department of the Interior. The NPS oversees 380 units of which 56 are designated national parks. Other units are designated national monuments, historical parks, memorials, historic trails, recreation areas, wild and scenic rivers, lakeshores, seashores, and battlefields. The U.S. Park Police are the law enforcement division of the National Park Service, with jurisdiction in all National Parks.The United States National Park system encompasses approximately 83.6 million acres (338,000 km²), of which more than 4.3 million acres (17,000 km²) remain in private ownership. The largest park is Wrangell - St Elias National Park and Preserve, Alaska. At 13,200,000 acres (53,000 km²) it is over 16 percent of the entire system. The smallest unit in the system is Thaddeus Kosciuszko National Memorial, Pennsylvania, at 0.02 of an acre (80 m²).
See also : List of United States National Parks