MCRRC Stone Mill 50 Mile Run 2026

The MCRRC Stone Mill 50 Mile Run is a 50-mile trail race in Montgomery County, Maryland, utilizing the Seneca Greenway and Muddy Branch trails. Organized by MCRRC, it typically occurs in late autumn, a time when wet conditions can make sections of the dirt path muddy. This race is designed for ultrarunners seeking a lengthy challenge on predominantly single-track terrain, differing from road ultras or flat loop courses. The course winds through wooded areas, crosses small streams, and follows trails that generally drain well but require careful footing when the ground is soft. A unique aspect of Stone Mill is its volunteer requirement: participants are expected to contribute at least six hours before race day to a local running club, another race, trail maintenance, or a running-related nonprofit like Girls on the Run or Let Me Run. This obligation operates on the honor system, without requiring verification, reflecting the community spirit that sustains local trails and races.