Hot Springs National Park, at the base of Hot Springs Mountain in Arkansas, is the smallest (5,549 acres)— and the oldest (established 1832)—national park. In its forty-seven thermal springs, 850,000 gallons of water flow per day, and water temperature averages 143 °Fahrenheit.
As early as the 170Os, visitors from all over the world came for the therapeutic benefits of the mineral water. In the early 1900s, the resort was known as "The American Spa," and the National Historic Landmark District—"bath-house row"—had the most opulent collection of bath-houses in North America. In 1962 the National Park Service purchased the Fordyce Bathhouse, renovated it, and reopened it in 1989 as a museum offering tours and information.
National Park of Samoa (9,000 acres, in the South Pacific) is second smallest and also the only U.S. park below the equator.