Ozark County is a county in the southern portion of the U.S. state of Missouri. As of the 2020 census, the population was 8,553. The largest city and county seat is Gainesville. The county was organized as Ozark County, named after the Ozark Mountains, on January 29, 1841. It was renamed Decatur County, after Commodore Stephen Decatur, from 1843 to 1845, after which the name Ozark County was restored.

Douglas County is a county located in the south-central portion of the U.S. state of Missouri. As of the 2020 census, the population was 11,578. The county seat and only incorporated community is Ava. The county was officially organized on October 19, 1857, and is named after U.S. Senator Stephen A. Douglas (D-Illinois) and later Democratic presidential candidate.