The National Park Service (NPS) is an American national park system that manages all national parks, many national monuments, and other conservation and historical properties with various title designations. It was created on August 25, 1916, by Congress through the National Park Service Organic Act and is an agency of the United States Department of the Interior. The NPS is charged with a dual role of preserving the ecological and historical integrity of the places entrusted to its management, while also making them available and accessible for public use and enjoyment.
The resources managed by the National Park Service include more than 400 areas covering more than 84 million acres (340,000 km2), which is more than 4% of the total land area of the United States. These areas are distinct from one another not only in terms of their size or location, but also in terms of their ecology, geology, history, and/or culture.