Indianola is a city in and the county seat of Warren County, Iowa, United States, located 19 miles (31 km) south of downtown Des Moines. The population was 15,833 at the time of the 2020 census. 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 major American Summer Opera Festival, and Simpson College.