c. 1870's - The Standing Rock Agency was moved in July 1873 to a site near the sacred Standing Rock or Inyan Woslata of the Sioux. A military fort was built and officially named Fort Yates in 1878. The Standing Rock Agency Stockade is the only original building remaining from the original fort, which was abandoned by the Army on September 13, 1903. It was the last of the forts in North Dakota to be closed.