The Seneca Creek Greenway Trail is a 24.2-mile (38.9 km) long trail that runs along Seneca Creek from the Potomac River to Watkins Road, with some parts maintained by the state of Maryland and some parts maintained by Montgomery County, MD[1] The 16.5 mile[2] state-maintained portion of the Seneca Creek Greenway Trail starts at the Potomac River near Riley's Lock.

The trail continues past Darnestown Road, Blackrock Mill and Clopper Lake until it reaches Maryland Route 355.

[3] The state-run portion of the trail ends at Maryland Route 355.

The county portion is a 7.8-mile natural-surface trail that continues to the north.

From there the trail runs to Watkins Mill Road, where there is also a parking area.