In 1879, tensions on Colorado's Western Slope rose as white settlers trespassed on treaty-designated Ute land and the U.S. government pressed the Utes to adopt white farming lifeways, contributing to escalating hostilities that culminated in the Meeker Massacre on September 29, 1879, at the White River Agency. Although the Uncompahgre Utes were not involved, demands that the Utes leave led to the arrival of U.S. cavalry and infantry under Colonel Ranald S. Mackenzie in May 1880 to watch both the Utes and the white trespassers. While the government negotiated the Utes' removal from the Uncompahgre Valley, soldiers built a permanent post called the Cantonment on the Uncompahgre, completed by summer 1881 in the fields before Fort Crawford. Agreements sent the White River Utes to the Uintah Reservation in Utah, and after commissioners determined that the expected reservation site near present Grand Junction lacked enough agricultural land, they used a clause in the agreement to place the new Ouray Reservation in Utah as well. After delaying as long as possible, and under threat of military action, 1,500 Utes departed for Utah under military escort on September 1, 1881. The post, later renamed Fort Crawford in 1886 for Captain Emmet Crawford, then remained as an economic benefit to local farmers and the new town of Montrose until the U.S. government withdrew all troops by December 1890 and auctioned the buildings to settlers. The fort had more than 32 buildings arranged around a 15-by-575-foot parade ground, including a hospital, quarters, barracks, storehouses, laundries, a shop, a shooting gallery, a gymnasium, and a large corral for 100 horses, and it had no defensive wall because its design assumed the Utes would be relocated. James A. Fenlon, who came to the valley in 1880 with trader's stores accompanying Mackenzie, opened a store at the cantonment, became first postmaster of the Uncompahgre post office on October 14, 1880, stayed after the fort closed to serve local settlers, and later acquired the land.