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Black Rock Mill – Pennyfield Lock loop from Boyds

Routes

Mountain biking trails

United States

Maryland

Montgomery County

Black Rock Mill – Pennyfield Lock loop from Boyds

Hard

3.3

(22)

riders

Black Rock Mill – Pennyfield Lock loop from Boyds

05:57

70.0km

640m

Mountain biking

Hard mountain bike ride. Very good fitness required. Suitable for all skill levels. The starting point of the route is accessible with public transport.

Last updated: August 17, 2026

Tips

Your route passes through protected areas

Please check local regulations for:

Chesapeake and Ohio Canal National Historical Park

Hoyles Mill Conservation Park

Seneca Creek State Park

South Germantown Recreational Park

Little Seneca Greenway Stream Valley Park

Waypoints

Start point

Train Station

Get Directions

654 m

Boyds Local Park

Nature Reserve

13.6 km

Black Rock Mill

Highlight • Historical Site

Just the walls remain of the 1815 Black Rock saw- and gristmill in Seneca Creek State Park. The structure was stabilized and representations of mill machinery were added in 1980.

Tip by

15.3 km

Seneca Creek State Park is a beautiful place to ride, especially during the fall when the landscape comes alive with color. Film fans might recognize it as a filming location for 'The Blair Witch Project'. Maybe don't visit at night...?

Tip by

38.5 km

Blockhouse Point Conservation Park

Nature Reserve

40.3 km

Bridge over Muddy Branch near Riley’s Lock

Highlight • Bridge

This is a very picturesque area, with the bridge, the creek, and the house up the hill beyond the field.

Tip by

41.2 km

Pennyfield Lock

Highlight • Monument

Lock 22, aka Pennyfield Lock, was built between 1829 and 1831, and the name came from the misspelling of the Pennifield family name. It has been restored and offers overnight stays to recreate the rustic feeling from that period.

Tip by

45.2 km

Inlet Lock

Lake

46.3 km

Riley’s lock

Highlight • Monument

Riley’s Lock is a fun, happening place. Every time I pass by it is bustling with activity. There are two row boat clubs along Seneca creek. There are kayak, jet …

Tip by

49.3 km

Seneca Bluffs Trail

Highlight (Segment) • Trail

This trail is ideal for hiking, running, and mountain biking due to its predominantly smooth terrain that doesn't feature many rocks or roots to navigate around. Throughout the majority of …

Tip by

51.9 km

Dry Seneca Creek Stream Crossing

Highlight • River

Crossing Dry Seneca Creek on stepping stones.

Tip by

62.9 km

Schaeffer Farm Trail System

Highlight • MTB Park

Schaeffer Farm Trail System is located in the heart of Seneca Creek State Park. No matter what you are up to, you will find it here: a small after work …

Tip by

70.0 km

End point

Train Station

Way Types & Surfaces

Way Types

55.4 km

8.03 km

2.39 km

2.19 km

1.63 km

310 m

118 m

Surfaces

54.6 km

6.13 km

4.92 km

4.17 km

173 m

< 100 m

Elevation

Nothing selected – click and drag below to see the stats for a specific part of the route.

Highest point (130 m)

Lowest point (50 m)

Weather

Saturday 22 August

26°C

18°C

-- %

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Comments

April 14, 2024,Muddy branch - C&O canal - Seneca ridge MTB loop

This is a very challenging tour to do in a day. The water fountain at Rliey's lock was not turned on and got dehydrated, and started cramping the last 5 miles.

August 3, 2025,Muddy Branch-C&O-Seneca Buffs, Greenway, Ridge Trails Loop

Not a boring trip at all. I realized how many connecting trails and parking lots there are in this area. MTB paradise.

December 1, 2024,Muddy Branch - C&O - Seneca Bluff - Seneca Ridge

Slow and sometimes slippery conditions today with the trail surface thawing.
The goal was to continue home via the Seneca Greenway and Upper Rock Creek trails. Fortunately, I had a bail out option.

March 29, 2025,Muddy Branch, Seneca Bluff and Seneca Ridge Trails

I had to shorten the ride as I was dehydrated with temperatures reaching 29 degrees today. Didn't carry enough water, and the water fountain at the Seneca Aqueduct was still shut down for the winter season.

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Our route recommendations are based on thousands of hikes, rides, and runs completed by other people on komoot.

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Black Rock Mill – Pennyfield Lock loop from Boyds

05:57h

70.0km

640m

Black Rock Mill – Pennyfield Lock loop from Boyds

Black Rock Mill

Seneca Creek State Park

Bridge over Muddy Branch near Riley’s Lock

Pennyfield Lock

Riley’s lock

Seneca Bluffs Trail

Dry Seneca Creek Stream Crossing

Schaeffer Farm Trail System

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