Missouri Mines State Historic Site occupies Federal Mill No. 3 in Park Hills, Missouri, United States, which processed the lead and zinc ore that was mined in the immediate area for many decades. The site's old power building features a geological and mining history museum and interpretive center focusing on the state's historic Old Lead Belt. The plant was built by the Federal Lead Co. in 1906-1907 and subsequently bought by competitor St. Joseph Lead Company in 1923.