Six Flags St. Louis is located in western St. Louis County in Eureka, Missouri and is known for its thrill rides and family entertainment. The park is open from early April through October. In October, the park is open only on weekends for what is called "Fright Fest," a month long Halloween Party! Hurricane Harbor, adjacent to Six Flags, is a 12-acre water park that is free with admission to Six Flags St. Louis. Hurricane Harbor is open from late May to early September. Special live music concerts are held throughout the summer months at the Old Glory Amphitheater, located in the park. Tickets to the concerts held at Old Glory are an additional fee to the park admission price.