Superior was founded by the Union Pacific Coal Company as a company town to house the workers for the largest coal mining operation west of the Mississippi River (back before the Great Depression). Nearby South Superior (also known as White City) was built to service the miners working in independent coal mines in the area. It seems the coal mines started closing in the 1930's, the last one finally going out of business in 1954. Since then, Superior's population has been slowly but steadily declining.