Coordinates: 38°30′10″N 90°38′42″W / 38.502736°N 90.645075°W / 38.502736; -90.645075
Eureka is a city located in St. Louis County, Missouri, United States between the cities of St. Louis and Pacific, along Interstate 44. It is a portion of the Greater St. Louis metro area. As of the 2010 census, the city had a population of 10,189. Since 1971, Eureka has been known as the home of the amusement park Six Flags St. Louis.