Daviess County is a county located in the U.S. state of Missouri. As of the 2020 census, the population was 8,430. Its county seat is Gallatin. The county was organized December 29, 1836, from Ray County and named for Major Joseph Hamilton Daveiss, a soldier from Kentucky who was killed in 1811 at the Battle of Tippecanoe.

Gallatin is a city in Daviess County, Missouri, United States. The population was 1,821 at the 2020 census. It is the county seat of Daviess County.