Big Horn Basin in northwest Wyoming is bounded by the Beartooth and Absaroka Mountains on the west, the Wind River and Owl Creek ranges on the south, the Pryor Mountains on the north, and the Big Horns on the east. Nearly elliptical in shape, it is about 140 miles long and 100 miles wide. The Wind River, fed by many tributaries in the Wind River Mountains, becomes the Big Horn River at "Wedding of the Water" in Wind River Canyon and serves as the basin's principal drainage. The river flows into Big Horn Lake, 71 miles upstream from Yellowtail Dam, at the center of the 120,000-acre Bighorn Canyon National Recreation Area administered by the National Park Service. The Pryor Mountains hold the first National Wild Horse Range established by an act of Congress and provide sanctuary for about 200 wild mustangs. In the basin, Sheep Mountain exposes classic geologic history in an anticline where strata from many eras are visible. Heart Mountain Relocation camp, northeast of Cody, confined more than 11,000 Japanese Americans during World War II from August 1942 until summer 1945, and despite harsh winters and austere living conditions, the Nisei brought water to the bench and successfully irrigated 1200 acres of farmland. The basin comprises Park, Big Horn, Washakie, and Hot Springs counties, whose seats are Cody, Basin, Worland, and Thermopiolis. Cody is home to the Buffalo Bill Historic Center, and Thermopolis has the world's largest mineral hot springs. Northeast of the basin, atop Medicine Mountain at an elevation of 9,642 feet, stands the prehistoric Medicine Wheel, a stone circle 80 feet in diameter designated a National Historic Landmark in 1970; nearby, in sharp contrast, an FAA air traffic control radar station built in 1962 monitors air traffic over three states. Beginning in the late 1800s, Mormon pioneers moved into the northern end of the basin, camped in tents along the "Stinking Water" (Shoshone) River until log homes could be built, and established Lovell, Cowley, and Byron. Today the basin's prime industries are farming, ranching, oil, mining, manufacturing, and tourism.