Two of the least densely populated states in the U.S. happened to be admitted on the same day. South Dakota was basically unexplored except by fur traders, and it wasn’t until Lewis and Clark’s expedition that North Dakota was explored.
On this day November 2nd, in 1889, North and South Dakota become the 39th and 40th state. They are the only states in history to have been admitted into the U.S. on the exact same day. This may come off as surprising, but in 1889 it was decided that the Dakota Territory would be split in half due to a large population.
The Dakotas are part of the Great Plains, a flatland covered with grasslands and prairies. The Battle of Wounded Knee would take place the next year in 1890 in South Dakota. This was the last major altercation between Americans and the Sioux tribe.