The first National Park, Yellowstone, was signed into law by President Ulysses S. Grant in 1872, followed by Sequoia and Yosemite, in 1890. The United States has 63 protected areas known as National Parks that are operated by the National Park Service. National Parks must be established by an act of the United States Congress but many current National Parks have been previously protected as National Monuments by the President under the Antiquities Act before being upgraded by Congress.