retreat from Oregon to near the Canada–US border in Montana. Numbering only 200 warriors, the Nez Perce "battled some 2,000 American regulars and volunteers of different military units, together with their Native auxiliaries of many tribes, in a total of eighteen engagements, including four major battles and at least four fiercely contested skirmishes." The Nez Perce were finally surrounded at the Battle of Bear Paw and surrendered. The Great Sioux War of 1876 was conducted by the Lakota under Sitting Bull and Crazy Horse. The conflict began after repeated violations of the Treaty of Fort Laramie (1868) once gold was discovered in the hills. One of its famous battles was the Battle of the Little Bighorn, in which combined Sioux and Cheyenne forces defeated the 7th Cavalry, led by General George Armstrong Custer. The Ute War, fought by the Ute people against settlers in Utah and Colorado, led to two battles; the Meeker massacre which killed 11 Native agents, and the Pinhook massacre which killed 13 armed ranchers and cowboys. The Ute conflicts finally ended after the events of the Posey War in 1923 which was fought against settlers and law enforcement. The end of the major Indian wars came at the Wounded Knee massacre on December 29, 1890, where the 7th Cavalry attempted to disarm a Sioux man and precipitated a massacre in which about 150 Sioux men, women, and children were killed. Only thirteen days before, Sitting Bull had been killed with his son Crow Foot in a gun battle with a group of Native police that had been sent by the American government to arrest him. Additional conflicts and incidents though, such as the Bluff War (1914–1915) and Posey War, would occur into the early 1920s. The last combat engagement between U.S. Army soldiers and Native Americans though occurred in the Battle of Bear Valley on January 9, 1918. Forts and outposts As the frontier moved westward, the establishment of U.S. military forts moved with it, representing and maintaining federal sovereignty over new territories. The military garrisons usually lacked defensible walls but were seldom attacked. They served as bases for troops at or near strategic areas, particularly for counteracting the Native presence. For example, Fort Bowie protected Apache Pass in southern Arizona along the mail route between Tucson and El Paso and was used to launch attacks against Cochise and Geronimo. Fort Laramie and Fort Kearny helped