The Great Sioux War of 1876, also known as the Black Hills War, was a series of battles and negotiations which occurred between 1876 and 1877 between the Lakota Sioux and Northern Cheyenne and the government of the United States. The cause of the war was the desire of the U.S. government to obtain ownership of the Black Hills. Gold had been discovered in the Black Hills, settlers began to encroach onto Native American lands, and the Sioux and Cheyenne refused to cede ownership to the U.S. Traditionally, the United States military and historians place the Lakota at the center of the story, especially given their numbers, but some Native Americans believe the Cheyenne were the primary target of the U.S. campaign.