Saturday, October 10th, 2026
Daredevil Brewing Co., Indianapolis IN
Ultra · 10K · 5K
52–70°F · some rain risk
See last 10 years
On this date: rain 2 of the last 10 years
2025
43–68°F
dry
2024
49–71°F
dry
2023
41–60°F
dry
2022
46–72°F
dry
2021
68–83°F
dry
2020
61–78°F
dry
2019
55–77°F
dry
2018
67–76°F
rain
2017
64–75°F
rain
2016
51–70°F
dry
Best months to race in Indiana →
About this race
**PLEASE NOTE IF YOU REGISTER AFTER 9/22, WE CANNOT GURANTEE MEDAL OR SHIRT**
Stay Obsessed. and the B&O Trail Association are proud to welcome you to the First Annual Big BO 50K Ultramarathon
Join your fellow run obsessed friends on the newly completed B&O Trail for a fast, exciting 50K experience unlike any other in central Indiana.
The journey begins at Daredevil Brewing Co. in the heart of Speedway — the Racing Capital of the World — and covers the entire length of the B&O trail through Marion and Hendricks County. You’ll Head east toward downtown Indy for a few miles before turning around head out to rural Hendricks County before making the return trip back to Speedway.
This course is flat, fast, and built for big goals. Whether you're dipping your toes into the world of ultrarunning for the first time or chasing a shiny new 50K PR, the Big BO 50K delivers the perfect stage to test your limits.
Stay Active. Stay Healthy. Stay obsessed.
Course map
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