Ava is the only incorporated city in Douglas County, Missouri, United States. The population was 2,894 at the 2020 census. Ava is the county seat of Douglas County. The city was founded in 1871. It was renamed Ava in 1881, the town's original name having been "Militia Springs."

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.