Gold discovered in the Black Hills in 1874 by two scientists attached to the Custer Expedition touched off the Black Hills Gold Rush in sacred Sioux land in South Dakota. During the Allison Commission in 1875, the Sioux refused to sell their reservation to the U.S. government, although this territory in the Dakotas had been assured to them in the Treaty of 1868. Despite promises to the contrary, the government could not discourage prospectors from invading once news of gold spread, and by 1876 thousands of fortune hunters were in the Black Hills as another round of war with the Sioux began. Sidney, already an established trailhead for shipping goods to the Nebraska Indian agencies, became a key starting point because its Union Pacific Railroad station was among the closest rail points to the Black Hills. From 1876 to 1881, the Sidney-Blackhills Trail carried much of the traffic, supplies, and gold to and from the Black Hills mining towns, and during 1878 to 1879 alone more than 22 million pounds of freight moved along the trail while about $200,000 in gold shipments moved south to Sidney and the railroad.