The National Park Service, a federal bureau in the Department of the Interior, manages all of the national parks in the United States. Common administration of the country's national parks did not exist until President Woodrow Wilson signed into law the National Park System Organic Act of 1916.
Yellowstone National Park, established in 1872, was America's first national park. By 1916 there were 40 national parks all administered by different agencies without a common goal. The creation of the National Park Service brought all national parks under one agency with the same mandate, to protect public lands set aside for native plants, animals, habitats, places of natural beauty and historical significance.