The National Park Service began on August 25, 1916, when President Woodrow Wilson signed the National Park Service Organic Act.
Before 1916, U.S. national parks and monuments were managed separately, often by the War Department, the Department of the Interior, or other federal offices. This arrangement made administration inconsistent and made it difficult to apply one national policy to widely scattered protected places.
The Organic Act created a dedicated federal bureau within the Department of the Interior. Its mission combined conservation with public enjoyment: scenery, historic objects, and wildlife were to be preserved while remaining available to visitors.
The date is sometimes confused with Yellowstone’s establishment in 1872, the Antiquities Act of 1906, or the appointment of Stephen Mather as the first NPS director in 1917. The agency’s legal creation belongs specifically to August 25, 1916.