By the Act of March 1, 1872, Congress established Yellowstone National Park in the Territories of Montana and Wyoming "as a public park or pleasuring-ground for the benefit and enjoyment of the people" and placed it "under exclusive control of the Secretary of the Interior." The founding of Yellowstone National Park began a worldwide national park movement. Today more than 100 nations contain some 1,200 national parks or equivalent preserves.

In the years following the establishment of Yellowstone, the United States authorized additional national parks and monuments, many of them carved from the federal lands of the West. These, also, were administered by the Department of the Interior, while other monuments and natural and historical areas were administered by the War Department and the Forest Service of the Department of Agriculture. No single agency provided unified management of the varied federal parklands. On August 25, 1916, President Woodrow Wilson signed the act creating the National Park Service, a new federal bureau in the Department of the Interior responsible for protecting the 35 national parks and monuments then managed by the department and those yet to be established.

The National Park System of the United States now comprises more than 400 areas covering more than 84 million acres in 50 states, the District of Columbia, American Samoa, Guam, Puerto Rico, Saipan, and the Virgin Islands.

This content is adapted from the National Park Service, "Quick History of the National Park Service."