when was south dakota accepted into the union
North Dakota And South Dakota are the 39th and 40th States Admitted to the Union On November 2, 1889, North Dakota and South Dakota were admitted to the Union as the 39th and 40th states. The first European explorers, Louis Joseph and FranÃ§ois de La VÃ©rendrye, entered the region in 1742 and 1743.