Hermann is a city in and the county seat of Gasconade County, Missouri, United States. It has been the county seat since 1842. It is near the c…Hermann is a city in and the county seat of Gasconade County, Missouri, United States. It has been the county seat since 1842. It is near the center of the Missouri Rhineland and south of the Missouri River. The population was 2,185 at the 2020 census.