South Dakota history By mikemogard Apr 30, 1803 Acquisition of South Dakota territory through Louisiana Purchase Video President Thomas Jefferson purchased the Louisiana Territory from France and its leader Napoleon Bonaparte. Sep 10, 1804 Lewis and Clark pass through South Dakota Video Meriweather Lewis, and William Clarke pass through South Dakota. Their job was to explore the new territory acquired in the Louisiana Purchase. Sep 10, 1817 First permanent settlement in South Dakota Supplemental Website Joseph La Framboise established Fort Pierre as the first permanent settlement in what is now South Dakota. Sep 10, 1874 Gold is discovered in South Dakota Video Gold is first discovered in western South Dakota. This discovery leads to a massive gold rush with people coming from all over the country. Nov 2, 1889 South Dakota becomes a state Supplemental Website South Dakota is given statehood. It becomes the 40th state in the United States. Sep 10, 1927 Work begins on Mount Rushmore Video Gutzon Borglum begins working on the Mount Rushmore monument. The monument was completed after Borglum's death in 1941.