Which was one of the causes that led to the Great Sioux War in 1876?

Gold was discovered in the Black Hills in 1874, on land the U.S. government had promised to the Sioux. The discovery brought miners and settlers into the area, increasing pressure on Sioux lands and contributing to the Great Sioux War of 1876. So the correct choice is “Gold was discovered in the Black Hills of South Dakota.”

AI-written and checked against the verified answer.