Koeltztown (KELTS'-town) is an unincorporated community in southern Osage County, Missouri, United States. It is located about seventeen miles southeast of Jefferson City and is one of the oldest settlements in Osage County. Founded in 1858, the community was named for its first postmaster, August Koeltze. While not Catholic, Koeltz donated land for a Catholic parish to encourage enough settlers to the area to establish a town around St.