Indianola is a city in Warren County, Iowa, United States, located 14 miles south of downtown Des Moines, Iowa. The population was 15,833 at the time of the 2020 census. It is the county seat of Warren County. Indianola is home to the National Balloon Classic, a nine-day hot air balloon festival held annually in the summer, the Des Moines Metro Opera, a world renowned major American Summer Opera Festival, and Simpson College.