Seneca Creek State Park

Earlier this year Clopper Lake experienced a boating closure due to a cyanobacteria bloom. The lake is currently testing within safe levels for recreational use, and the lake has reopened to private recreational boating.

Visitors to Clopper Lake should limit direct contact between lake water and open wounds and avoid ingesting lake water. Fish caught in the lake must be cleaned thoroughly and all entrails discarded.​ We also recommend that pets be kept away from lake water at all times.

​ The Maryland Department of Natural Resources will continue to monitor conditions in the lake. If visitors or their pets experience any symptoms of illness after being near the water, a doctor or veterinarian should be consulted. For more information please call the Maryland Department of Health Helpline at 1-866-703-3266.

Clopper Lake

Park Reservations

To reserve one of our rental picnic areas or pavilions​, contact the Maryland Park Service reservation desk at 1- 888-432-2267 or

For all other questions, contact the Park:

Montgomery County

Seneca Creek State Park
11950 Clopper Road
Gaithersburg, MD 20878

8 a.m. to Sunset, March-October
10 a.m. to Sunset, November-February

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Service Fee Charges:
Weekends and Holidays, April-October: $3 a person for Maryland residents
$5 a person for Out-of-State residents


The park, comprised of 6,300 acres, extends along 14 scenic miles of Seneca Creek, as it winds its way to the Potomac River. The Clopper Day-Use Area contains many scenic areas, including the 90-acre Clopper Lake, surrounded by forests and fields. Picnicking, boat rentals, trails and a tire playground are just some of its recreational opportunities. A restored 19th century cabin and a self-guided path interpret the history of the area. Over 50 miles of trails are open for hiking, horseback riding and bicycling which wind through a variety of habitat.

Note: Swimming and wading are not permitted in Clopper Lake at Seneca Creek State Park. The closest Maryland State Parks with lifeguarded lake swimming are Cunningham Falls State Park and Greenbrier State Park. Wading is permitted at your own risk in Great Seneca Creek, the free flowing creek which runs the length of Seneca Creek State Park.

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Mountain Biking

Mountain Biking in Seneca Creek State Park​​ ​

Schaeffer Farm Trail System

​Schaeffer Farm is the hub of a trail system unique in Maryland. The trails at Seneca Creek State Park provide the backbone of a network that extends into most of the upcounty area. Configured in a series of loops, you can enjoy as few as four miles or go for an all-day adventure. It is possible to do a trail loop stretching 60 miles or more when you leave the trailhead. Linking the Seneca, Muddy Branch, and Potomac watersheds, visitors can journey from Schaeffer to Damascus to the Potomac and back.

One of these larger loop​s has been recognized by the International Mountain Bicycling Association as one of the best and most important routes in the country.​​