Stone Mill 50 Mile Run
Gaithersburg, United States • 7 Nov 2026
Event Overview
The Stone Mill 50 Mile Run is a trail race located in Montgomery Village, Maryland. The course highlights the natural scenery of Montgomery County by utilizing the Seneca Greenway and Muddy Branch trails. Participants navigate a route consisting primarily of single-track dirt trails through forested areas and rolling terrain.
Course Details
The race distance is 50 miles. The path includes several small stream crossings that runners must navigate. While many sections of the trail system are designed to drain effectively, certain portions of the course may become muddy if there is wet weather leading up to or during the event.
Participation and Volunteering
Registration for the event opens in May and closes at the end of August. As part of the event's philosophy, participants are asked to commit to at least six hours of volunteer service with a local running club, a trail maintenance crew, or a running-related non-profit organization prior to race day. This commitment is based on an honor system, and no official proof of service is required to enter the race. Visit the organization's website for the most recent information.