In january 1876, the sioux and the cheyenne were ordered to leave the black hills area of south dakota, which had been designated by treaty for them because

In January 1876, the Sioux and the Cheyenne were ordered to leave the Black Hills area of South Dakota, which had been designated by treaty for them because gold was discovered in the Black Hills of South Dakota and the US government was unable to keep gold prospectors and others out of the area which had been given to the Sioux in a treaty. I hope that this is the answer that you were looking for and it has helped you.