Stone Mill 50-Miler

This 50-mile trail run showcases the beauty of both the Seneca Greenway and Muddy Branch trails in Montgomery County, Maryland. The course traverses forested, rolling terrain on a primarily single-track, dirt trail. There are small stream crossings. Most of the course drains well, but parts can be muddy in wet weather.

This race is an RRCA National Championship Event. This series is the largest grassroots-organized running series in the U.S., with over 200 races participating that attract nearly 300,000 participants. The goal of the series is to celebrate well-run, community-focused events and to award top-performing runners.

The registration fee is $65 as of 2/26/25.