There are 7 US Post Offices in Moniteau County serving a total of 15,056 residents equating to 2,151 residents per post office. It's estimated that approximately 24,031 packages are handled across the 7 county post offices annually. Moniteau County is a county located in the U.S. state of Missouri. As of the 2010 census, the population was 15,607. Its county seat is California. The county was organized February 14, 1845 and named for the Moniteau Creek. 'Moniteau' is a French spelling of Manitou, Algonquian for the Great Spirit. Moniteau County is part of the Jefferson City, MO Metropolitan Statistical Area."