High Quality Content by WIKIPEDIA articles! Eureka is a city located in St. Louis County, Missouri, United States, between St. Louis and Pacific, Missouri, along Interstate 44. As of the 2010 census, the city had a total population of 10,189. The city is 2 miles (3 km) west of the former site of Times Beach, the site of dioxin contamination discovered in the 1980s; the area was cleaned up and became Route 66 State Park. Since 1971, Eureka has been known as the home of the amusement park formerly known as Six Flags Over Mid-America and now called Six Flags St. Louis. Local news coverage for the town and some of its neighbors is provided by the Tri County Journal and the Washington Missourian.