Half Marathon

The Great GO! St. Louis Halloween Race

GO! St. Louis takes its costume-heavy fall race weekend to Eureka, where the half follows country roads along the Meramec River into Route 66 State Park.

Next raceSunday, October 25, 2026
Distance categoryHalf Marathon
LocationEureka, Missouri
Get alertsLast checked August 14, 2026

Quick facts

  • Organized by GO! St. Louis, the nonprofit behind the region's largest race weekends.
  • Half marathon course runs river-valley country roads into Route 66 State Park.
  • Costume contest culture with a two-day schedule, including a dog-friendly mile.
  • Late-October date usually brings cold starts and crisp racing weather.

About the Great GO! St. Louis Halloween Race

GO! St. Louis, the nonprofit behind several of the region's biggest race weekends, stages its Halloween event from Eureka's business district. Costumes are the point, with a contest and trick-or-treat village around the racing. Sunday belongs to the half marathon and 10K, while Saturday holds the 5K, fun run, and a costume dog walk.

Course

The half leaves Eureka's business district for country roads along the Meramec River, then takes a path under I-44 for a loop on Blakey Road inside Route 66 State Park before returning. It runs quieter and more rural than the organizer's city races, with the river valley setting doing most of the scenery work.

Race-day weather

Late October mornings near the Meramec often start in the 30s or 40s, with frost possible at the start and mild air by midday. Layers that can be shed matter more than heat planning.

Past Great GO! St. Louis Halloween Race dates and results

YearDateStatusResults
2026Sunday, October 25, 2026Upcoming

The Great GO! St. Louis Halloween Race FAQ

When is The Great GO! St. Louis Halloween Race?

The 2026 Great GO! St. Louis Halloween Race is on Sunday, October 25, 2026.

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