Hot Springs National Park, 5,549 acres (2,247 hectares), W central Ark.; est. 1921; nearly surrounded by the city of Hot Springs. Visited by Spanish explorer Hernando De Soto in 1541, the springs, long used by Native Americans for medicinal purposes, became a Federal Reservation in 1832. More than a million gallons of water a day, with an average temperature of 143°F (62°C), flow from 47 springs. The National Park Service collects, cools, and supplies water to bathhouses in and out of the park. See National Parks and Monuments (table).