Since June 30, 1864 a part of what is now Yosemite National Park has been protected. Yosemite Valley and the Mariposa Grove of Giant Sequoias were granted to the State of California as an inalienable public trust. Eight years later in 1872, Yellowstone was established as the first official national park. In an effort to counter the destruction of the region around the state reserve, and with considerable effort by John Muir, Yosemite National Park was created on October 1, 1890. The military provided the initial administration of the park from Wawona. The military established and enforced many of the current policies of the parks, such as the ban on hunting. In 1906, California ceded the Valley and Mariposa Grove back to the federal government and civilian park rangers took over from the military in 1914 as WWI was looming on the horizon. The National Park Service was established in 1916 to administer all national parks "Promote and regulate the use of the federal areas known as national parks, monuments and reservations by such means and measures as conform to the fundamental purpose of the said parks, monuments and reservations, which purpose is to conserve the scenery and the natural and historic objects and the wild life therein and to provide for the enjoyment of the same in such manner and by such means as will leave them unimpaired for the enjoyment of future generations."

As usage increased (one million in 1954, two million in 1976, and four million in the mid-1990s, and 3,242,644 in 2006 (or, roughly 1 visit by everyone in Los Angeles) -- of the units of the park service called National Parks, Yosemite ranks #3 -- behind the Great Smoky Mountains and Grand Canyon, ahead of Olympic and Yellowstone) more restrictions were placed on where you could drive, where you could park, where you could camp, how trash was handled, and on other destructive activities. The selected years on the graph show monthly totals for recent years including the year of the flood in January 1997, and 1995 before the flood. The 1979 data is included to show some of the historical trends. Given the damage to the campground and Lodge area, the overnight stays were impacted by the flooding even more than the total visitor counts.