National Parks
The United States has 61 protected areas known as national parks that are operated by the National Park Service, an agency of the Department of the Interior.
National parks must be established by an act of the United States Congress. A bill creating the first national park, Yellowstone, was signed into law by President Ulysses S. Grant in 1872, followed by Mackinac National Park in 1875 (decommissioned in 1895), and then Rock Creek Park (later merged into National Capital Parks), Sequoia and Yosemite in 1890.
