In the early 1860s the Oglala Sioux leader Chief Red Cloud fought to keep the U. S. Army from opening the Bozeman Trail, which led to the Montana gold fields through Sioux hunting areas in the Dakota Territory. Between 1866 and 1868 Red Cloud and his allies besieged forts along the trail until in 1868 the U.S. government agreed to abandon it. Red Cloud signed the 1868 Treaty of Fort Laramie Wyoming on April 29, 1869. The U. S. government agreed to close the Bozeman Trail, and in the treaty included a provision that assured Sioux ownership of the Great Sioux Reservation-more than 60 million acres west of the Missouri River. During the summer of 1874, a military expedition under General George Armstrong Custer confirmed that the Black Hills contained gold. At that time, the Black Hills were part of the Great Sioux Reservation. Initially, the federal government attempted to keep eager miners from entering the region, as it was oblige to do under the terms of the treaty. By mid-summer 1875, hundreds of miners had evaded military patrols to prospect in the Black Hills. In September federal officials met wit
h Sioux leaders and attempted to buy mining rights, but the U.S. government considered the price to high, and the gold rush began after negotiations with the Sioux collapsed. In October, the federal government withdrew its military forces from the area, giving tacit permission for gold prospectors to enter, and they came by the thousands. The flood of miners into the Black Hills also provoked the Sioux and groups of Cheyenne to attack to prevent the loss of their land. Much of the fighting between the U. S. government and the Native Americans, led by Hunkpapa Sioux Sitting Bull and the Oglala Sioux Crazy Horse, took place outside the area of present-day South Dakota, including the Battle of the Little Bighorn in 1876, in which Sioux and Cheyenne killed Custer and about 260 U. S. soldiers near the Little Bighorn River in what is now Montana. Red Cloud did not support the radical leader Crazy Horse, but he was not willing to sacrifice the Black Hills. Because of superior resources and weapons, the U.S. Army defeated the Sioux and forced them onto the reservations. Red Cloud was removed as Oglala chief after a dispute with a government agent in 1881, and he spent his last years at Pine Ridge Reservation in South Dakota.