Montgomery Village, Maryland · Trail
Official site ↗Stone Mill 50 Mile
A November 50 miler on the Seneca Greenway and Muddy Branch trails of Montgomery County, Maryland, from Montgomery Village, with about 4,000 feet of climb and 13 hours.
Distances
- Distance
- 50 mi (80 km)
- Vert gain
- 4,000 ft (1,200 m)
- Cutoff
- 13 hr
| Distance | Vert gain | Cutoff |
|---|---|---|
| 50 mi (80 km) | 4,000 ft (1,200 m) | 13 hr |
About
Stone Mill is the Montgomery County Road Runners Club's 50 miler, run each November from Stedwick Elementary School in Montgomery Village, in the Maryland suburbs north of Washington. It follows the Seneca Greenway and Muddy Branch trails through forested, rolling country, with small stream crossings and about 4,000 feet of climbing. It falls two weeks before the JFK 50 Mile.
The cutoff is 13 hours, finishing by 7:00 p.m., and the race says it is strictly enforced under its park permits. In 2025 Spencer Imbach won in 6:58:52, and Elena Makarevich won the women's race in 8:45:47.
Course
A lollipop from Stedwick Elementary School. The course heads out through the Route 355 and Riffle Ford Road aid stations to a loop that reaches the C&O Canal at Pennyfield Lock (mile 24.3) and turns back past Stone Mill (mile 27.8), then returns on the same trail, passing Riffle Ford at mile 42 and Route 355 at mile 46. It is mostly dirt, on the Seneca Greenway and Muddy Branch trails, with about 4,000 feet of gain.
The start is 6:00 a.m. and the finish closes at 7:00 p.m. Intermediate cutoffs run from 12:30 at Pennyfield to 6:40 at Route 355.
How to register
Entry is first come, first served on RunSignUp for runners 18 and over, and it stays open until race morning. The race does not publish course records.