The United States has 58 protected areas known as national parks, which 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. The first national park, Yellowstone, was signed into law by President Ulysses S. Grant in 1872, followed by Sequoia and Yosemite in 1890. The Organic Act of 1916 created the National Park Service "to conserve the scenery and the natural and historic objects and wildlife 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."[1] National parks usually have a variety of natural resources over large areas.[2] Many of them had been previously protected as National Monuments by the President under the Antiquities Act before being upgraded by Congress. Seven national parks are paired with a National Preserve, six of which are in Alaska. While administered together, they are considered as separate units and their areas are not included in the figures below. The newest national park is Great Sand Dunes, established in 2004.
Twenty-seven states have national parks, as do insular areas American Samoa and the United States Virgin Islands. Alaska and California have the most, each with eight, followed by Utah with five and Colorado with four. The largest national park is Wrangell – St. Elias, at over 8,000,000 acres (32,000 km2), followed by three more in Alaska; the smallest is Hot Springs, at less than 6,000 acres (24 km2). The total area protected by national parks is approximately 51,900,000 acres (210,000 km2), for an average of 895,000 acres (3,620 km2) but a median of only 317,000 acres (1,280 km2).[2] The most-visited national park is Great Smoky Mountains, with over nine million visitors in 2008, followed by the Grand Canyon, with over four million.[3] Fourteen national parks are designated World Heritage Sites.[4]
A few national parks are no longer designated as such, having been redesignated or disbanded. Other designations of National Park Service areas are sometimes also called national parks; they are listed here.
For more information Please visit : http://en.wikipedia.org/wiki/U.S._National_Park
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