Wildwood is a city in St. Louis County, Missouri, United States. It is located in the far western portion of the county. As of the 2020 census, the population was 35,417. Wildwood is the home of the Al Foster Trail, and numerous other trails, parks, and reserves such as Rockwoods Reservation and Babler State Park.

Eureka is a city in St. Louis County and Jefferson County, Missouri, adjacent to Wildwood and Pacific. It is in the extreme southwest of the Greater St. Louis metro area. As of the 2020 census, the city had a population of 11,646. Since 1971, Eureka has been known as the home of the amusement park Six Flags St. Louis.