Pennyfield Lock – Swains Lock loop from Rockville

If you're looking for a rewarding day out on two wheels, the Pennyfield Lock – Swains Lock loop from Rockville offers a moderate mountain biking experience that's well worth your time. This 39.8-mile (64.0 km) route, with 1439 feet (439 metres) of elevation gain, takes approximately 4 hours and 46 minutes to complete, making it a solid ride for those with good fitness looking for varied terrain and historical sights.

What to expect on Pennyfield Lock – Swains Lock loop from Rockville

This loop largely follows the historic C&O Canal towpath, offering a journey through peaceful forested trails, past lakes and creeks. While much of the towpath has minimal elevation change, don't expect a perfectly smooth ride; the terrain varies from excellent conditions to rougher sections with mud, gravel, grass, and roots, especially after rain. A major highlight is the incredible sight of Great Falls, where the Potomac River dramatically flows over jagged rocks through Mather Gorge. As you head south of Swains Lock, be prepared for more technical elements like rock gardens and 'baby heads' (small, embedded rocks), which add a bit more challenge for most mountain bikers.

Planning your visit

Given the length and varied terrain, good fitness is key for this moderate mountain bike ride. The trail is popular for other recreational activities, so you might encounter walkers and joggers, especially on pleasant days. While specific parking or public transport details aren't highlighted, the historic Pennyfield Lockhouse (Lock 22) and Swains Lockhouse (Lock 21) are notable features along the way, with Pennyfield Lockhouse even offering overnight stays for a unique historical experience.

Trail details

• Distance: 39.8 miles (64.0 km)
• Elevation gain: 1439 feet (439 metres)
• Difficulty: moderate
• Estimated time: 4 hours and 46 minutes