At a Glance

Hours: Daylight hours year-round.

Cost: Free.

Tips: Spotting scope recommended. ◾ Restrooms are at the parking areas. ◾ Picnic tables are located at Riley’s and Violette’s Locks. ◾ For more amenities, see

Best Seasons: Year round.

Local MOS Chapter: Montgomery Bird Club

C&O Canal – Pennyfield, Violette’s & Riley’s Locks

Pennyfield – 12100 Pennyfield Lock Road, Potomac, MD 20854
Violette’s – 13001 Violettes Lock Road, Germantown, MD 20874
Riley’s – 13001 Rileys Lock Road, Germantown, MD 20837
(301) 495-4500

The stretch of the C&O Canal containing Pennyfield Lock, Violette’s Lock, and Riley’s Lock has a rich diversity of habitat, including the Potomac River, flooded portions of the C&O canal, and adjacent woodlands, impoundments, and marshes that provide for varied birding opportunities for migrating, nesting and over-wintering birds. Violette’s Lock itself is the #1 eBird hotspot in Montgomery County, with over 270 species reported, and Riley’s Lock and Pennyfield Lock are not far behind.

This 3.2-mile stretch of the C&O Canal is but a small portion of the 184.5-mile C&O Canal National Historical Park, operated by the National Park Service. The canal parallels the Maryland shore of the Potomac from Allegany County in western Maryland all the way to Washington, DC. For reference, it helps to know that the locks along the canal, used in earlier times to control water levels for navigation, are numbered starting at the downstream end at Washington, DC., and go up to Lock 75 near Cumberland in Allegany County. Locations along the canal are also denoted by mileposts, which again are numbered starting at Washington, DC.

Pennyfield Lock is Lock 22, located at Milepost 19.6; Violette’s Lock is Lock 23, at Milepost 22.1; and Riley’s Lock is Lock 24, at Milepost 22.8. The Riley’s Lock area is also known as Seneca. The National Park Service map at the trail link map below provides a good overview, and another good reference is the detailed “Park Planner and Recreational Guide by Milepost” (…).

Some of the best views of the Potomac River are provided at Violette’s Lock and Riley’s Lock.  Note that the river and canal run approximately east-west along this stretch. An early morning birder might want to proceed west from Pennyfield toward Violette’s and Riley’s in order to keep the sun at your back. The approximately 3.2 mile walk from Pennyfield to Rileys could be birded in a half-day. The approximately 6.4 mile round trip would constitute a full day of birding. An alternative would be to bird with a friend and use two cars, parking one at each end.


Over 265 species have been reported on eBird from this section of the C&O Canal. There are separate eBird hotspots for the three canal locks:

Of note in this area of the canal are the abundant warblers during spring migration, and many nesting species including Bald Eagle, Prothonatory Warbler, occasional Cerulean Warbler, Louisiana Waterthrush, Baltimore Oriole, and owls, flycatchers, swallows, herons and woodpeckers. Migrants of note include Bonaparte’s Gull and Forster’s Tern. Over-wintering waterbirds include ducks, grebes, and coots. A good assortment of shorebirds turns up during migrations. The Pennyfield-Violette’s-Riley’s area is known for sometimes hosting Sooty Terns or a Pomarine Jaeger in the aftermath of a hurricane.


Paved at Riley’s Lock; graded gravel and sand at Violette’s and Pennyfield.

Special Features:

Some sections of the C&O Canal Towpath are wheelchair accessible, but the path is graded gravel and conditions are subject to change depending on weather. For more about accessibility, see ◾ Many spots along the canal offer boat launch and other facilities. See the brochure at for a handy summary of features at each site. Or see for more details. ◾ The C&O Canal is rich in history. Explore the many historical features of the C&O Canal National Historical Park. ◾ The Canal Trust has produced a mobile app, the C&O Canal Explorer, with over 600 points of interest mapped  in a searchable format, allowing you to find hiking trails, campgrounds, history, trailheads, parking, and more at a glance, along the entire length of the Canal.  The app is available to download for 99 cents and runs on Android and IOS devices. ◾  Wake up with the bird along the Canal: through the Canal Quarters Program, visitors may arrange for overnight stays at seven historic lockhouses along the Canal: five in Montgomery County, one in Frederick County, and one in Washington County. See for details. ◾  The C&O Canal and bordering lands within Montgomery County are part of the Lower C&O Canal Important Bird Area, as designated by the National Audubon Society. ◾ The local chapter of the Maryland Ornithological Society is the Montgomery Bird Club, which offers field trips and meetings with informative programs, all free and open to the public.◾ The Montgomery Bird Club has published A Birder’s Guide to Montgomery County, Maryland; this comprehensive, detailed printed book covers 17 major birding sites plus 18 “little treasures” in the county. To order, see


These directions will take you sequentially from Pennyfield to Violette’s to Riley’s Locks.

To reach Pennyfield Lock from I-495/DC Beltway: Take Exit 39 for MD Route 190/River Road. Proceed west on River Road for approximately 8.5 miles and then turn left (south) onto Pennyfield Lock Road; the preceding intersection is Travilah Road. Follow Pennyfield Lock Road for about 0.7 miles to its dead-end near the C&O Canal. Park in the lot.

To reach Violettes Lock from Pennyfield Lock: Return to River Road and turn left (west) and drive approximately 2.6 miles to Violette’s Lock Road. Turn left (south) and proceed about 0.6 miles to the parking area at the end of the road.

To reach Riley’s Lock/Seneca from Violette’s Lock: Return to River Road and turn left, which will take you northwest. At the T-intersection with Seneca Road, turn left to remain on River Road. Then turn left (south) onto Rileys Lock Road at the bottom of long hill). It is just under 1 mile along River Road from Violette’s Lock Road to Riley’s Lock Road. Proceed about 0.7 miles to the parking area at the end of the Riley’s Lock Road.

Nearby Sites:

Seneca Creek State Park; McKee Beshers (Hughes Hollow) WMA; Meadowside Nature Center; Lois Y. Green Conservation Park; Lake Needwood; Little Bennett Regional Park; Blue Mash Nature Trail


Bottomland DeciduousHedgerows Forested SwampFreshwater Marsh or FloodplainMud Flats (Tidal or Non-Tidal)Rivers & Streams


BeginnersBicycle Trails (Bikes may be prohibited on some trails)Boat or Canoe/Kayak LaunchFishingFree - No Entry FeeHiking/Walking TrailsHistorical FeaturesLake, Pond, Bay, River, OceanParkingPets AllowedPicnic AreaRestroomsWheelchair Accessible FeaturesYoung People / Families


#1 Hotspot in County or CityAudubon Important Bird AreasC&O Canal AccessHiker-Biker Trails (Paved)National Parks & MonumentsThe Rivers of the Western ShoreWater Trails