At a Glance


  • Grounds are open from dawn to dusk, year-round.
  • The historic house and museum exhibit are open April through October on Saturdays from 10 am to 4 pm, and on Sundays from 12 noon to 4 pm.
  • Outdoor archaeological excavations are available to view on most Saturdays from April through October.

Cost: Free.

Tips: Bring a scope. ■ If you plan to walk the Old Railroad Bed Trail, wear sturdy hiking boots and be prepared for ticks. ■ If mobility-impaired, you can stay in the car and get good views of the river from a pull-off on the entrance road. ■ Hunting is conducted on portions of the Mount Calvert property. Be aware of hunting seasons and plan your visit accordingly. ■ No restrooms available most of the time, but restrooms in the house are available during the limited hours when the house is open. Nearest alternative for restrooms is at Patuxent River Park – Jug Bay Natural Area Visitor Center.

Best Seasons: Year-round.

Breeding Bird Atlas Block: Bristol SW

Local MOS Chapter: Patuxent Bird Club

Patuxent River Park – Mount Calvert Historical & Archaeological Park

16801 Mount Calvert Road, Upper Marlboro, MD 20772
(301) 627-1286

Mount Calvert Historical and Archaeological Park is part of the Patuxent River Park system managed by the Prince George’s County Parks and Recreation Department/Maryland-National Capital Park and Planning Commission. Mount Calvert is worth a visit for the spectacular view of the Patuxent River and its marshes at the north end of Jug Bay. During most of the year, these marshes are filled with birds. The marshes hold one of the largest stands of native wild rice on the East Coast; the wild rice is an important food for birds migrating through the area in the fall, and also offers nesting habitat for a number of species.

Mount Calvert is on the western shore of the Patuxent River, perched high on a point of land where the Western Branch flows into the main channel of the river, providing a panoramic view of the river and the head of Jug Bay. The northwest boundary of the park property roughly follows Charles Branch, which is a tributary of Western Branch. Across the marshes to the north is another historic property, Billingsley House, which sits on a prominent knoll and has been a landmark for boaters on the river for 300 years or more. Directly across the Patuxent River is the Jug Bay Wetlands Sanctuary of Anne Arundel County, and to the south on the Prince George’s side of the river is the Jug Bay Natural Area of Patuxent River Park. See the overview map of Jug Bay area parks at the link at left. The entire area is a birder’s Mecca, where you can happily spend days wandering through the many preserved tracts of land or exploring the Patuxent River and its tributaries by boat.

The eBird list for Mount Calvert has over 200 species, quite a diversity for a medium-sized site – only about 189 acres, including the main parcel near the house, plus the woods and marsh to the west, near the Charles Branch of the Patuxent River. The compact size of the site means it can be thoroughly birded in an hour or two.

To reach Mount Calvert, simply follow Mount Calvert Road to its end at the property. A short gravel driveway leads from the entrance gate to the house area. Where the entrance road makes a sharp curve to the left, pull over to the side to take in the view across the river and marshes. If there are many birds on the water, you can set up your scope here. Or continue down the entrance drive to park in a designated grassy area under the shade of old trees, where the resident Northern Mockingbird will greet you. Check the trees around the parking area for warblers and flycatchers in spring and early summer and sparrows in winter. The electric wires along the entrance road are a favored gathering spot for swallows and martins in summer.

A gravel road (foot traffic only) continues past the house down to the water’s edge, where a wharf formerly provided a loading area for tobacco being shipped out by barge. The wharf area is now a soft launch for canoes and kayaks, and a short floating pier provides a good vantage point for birding. This is a good spot to set up your scope and to listen for Marsh Wrens, Virginia Rails, and Sora. Osprey nest on platforms all through the marsh, and there are several Bald Eagle nests in the vicinity. The strip of trees bordering the lane down to the pier is a magnet for songbirds such as Baltimore Oriole, Orchard Oriole, Brown Thrasher, and Common Yellowthroat and for Yellow-rumped Warblers in winter. The grassy edge of the lane attracts sparrows in fall and winter, including Savannah, Field, and sometimes a White-crowned.

The large fields along the entrance drive are planted with agricultural crops that vary from year to year. The crop fields provide good habitat for a variety of field birds that changes depending on season: American Pipits, Horned Larks, Savannah Sparrows, Field Sparrows, Eastern Meadowlarks, perhaps a few Bobolinks during migration. There are dirt roads through the fields and mown strips around the edges, and it is permissible to walk there, but driving in the fields is not allowed. If there are newly planted crops, be careful to stay on the lane and do not trample the crops.

Once you’re done scoping the river and marshes and exploring the fields and hedgerows, you can return in your car to the entrance gate; just outside the gate is a small parking area, with room fo two or three cars, outside a gated trail that heads north. This foot-trail runs along the bed of a historic railroad (the rails and ties are long gone) that carried tourists from Washington, DC to Chesapeake Beach in Calvert County. The railroad bed trail runs in a straight line to the Charles Branch of the Patuxent River, a one-way distance under a half-mile, passing between hedgerows and woods edges that offer excellent habitat for songbirds. This is a good spot to check for Summer Tanagers and both orioles in spring and summer. Carry your scope with you, because near the trail’s end at Charles Branch (no bridge, and impassable on foot), there are freshwater marshes to the left and to the right that may have waterfowl in winter and shorebirds, particularly snipe and yellowlegs, during migration. Wood Ducks and possibly Hooded Mergansers nest here. There are one or more Bald Eagle nests in the area, so be alert and check the tops of the largest trees.

Historical note: Although birders are drawn to the habitat, others visit for the history. Mount Calvert was an important tobacco plantation in the 18th and 19th centuries, and was the site of the first county seat of Prince George’s County, from 1696 to 1721. The existing brick plantation house was built in 1796, with additional construction in 1809. Today the house is a museum with exhibits concerning the intertwined local history of tobacco growing, slavery, and pre-colonial Native American settlements. The area also saw significant activity in the War of 1812, when invading British warships came up the river, and this is documented in outdoor placards near the house. There are active archaeological excavations underway to uncover more of the history of the site.


Over 200 species have been reported on eBird from Mt. Calvert. The Patuxent River Park’s official bird checklist for the Jug Bay area of the Patuxent River lists 305 species.

Soras are a specialty at Mount Calvert. They nest in the marshes in small numbers, but the numbers increase during fall migration, when more arrive to feed on wild rice in the marshes; walk down to the canoe/kayak launch to listen for them. Virginia Rail is also possible. Also check here for Marsh Wrens, Least Bitterns, terns, herons and egrets in spring and summer. During the summer of 2018, a Roseate Spoonbill that had been hanging out at Chesapeake Beach was viewed from the pier, briefly lurking in the marsh near Billingsley House to the north.

In winter, stand on the knoll near the house and parking area to scope the waters of the river for waterfowl and gulls. In late summer, use that vantage point to look for terns.

Check the agricultural fields in winter for pipits and sparrows, including Savannah and White-crowned. Grasshopper Sparrows may be present in summer, and Swamp Sparrows use the marshes in winter. American Tree Sparrows use the hedgerows of the railroad bed trail some winters. All year, walk the trail along the old railroad bed to look for songbirds, plus waterfowl and shorebirds in the Charles Branch marsh.

Wheelchair Access:

It is possible to get a good view of the river and marshes from the car, or near the car, along the entrance drive, so this location is good for those who are mobility-impaired. However, neither the house nor the railroad bed trail are wheelchair-accessible. There are a couple of picnic tables near the parking area, but no other visitor amenities. No accessible restrooms.

Pet Policy: 

Pets are allowed on leash; pick up after your pet.

Special Designations:

Special Features:

There are restrooms in the house but these are only available on days when the house is open for visits.

MNCPPC has an online brochure that describes the historical aspects of Mount Calvert. Archaeological excavations at Mount Calvert are generally open for visits on most Saturdays from April through October. The house has exhibits focusing on the local history of tobacco plantations, enslaved peoples, and Native Americans. Outdoor placards detail events of the War of 1812.

The Patuxent Riverkeeper is a grass-roots organization dedicated to improving the health of the Patuxent River and connecting local communities to the river. The Riverkeeper organization has a headquarters building on the river at Nottingham, just south of the Jug Bay Natural Area and Merkle NRMA. Patuxent Riverkeeper rents canoes and kayaks to members and to the public and hosts public events throughout the year.

Mount Calvert is one of the sites on the Patuxent Water Trail.

Local MOS Chapter:

The local chapter of the Maryland Ornithological Society is the Patuxent Bird Club, which offers field trips and meetings with informative programs, all free and open to the public.


Park in the grassy area (signed) under trees near the house; you may also park near the  start of the railroad bed trail near the main entrance gate. Do not park in crop fields or in the signed “No Mow” areas. Do not park in front of the private residences near the entrance gate.


From US Route 301 at MD Route 4 near Upper Marlboro: Go south on Route 301 for about 4.0 miles and turn left (southeast) onto MD Route 382/Croom Road. Proceed on Croom Road for about 2.3 miles; then turn left onto Mount Calvert Spur Road. In 900 feet, at the T-intersection, turn left again (east), onto Mount Calvert Road. The entrance gate to Mount Calvert is straight ahead at the end of the road (about 2.8 miles).

Nearby Sites:

Prince George’s County: Beltsville Agricultural Research Center (restricted access) ■ Bladensburg Waterfront Park, Colmar Manor Community Park & Anacostia River Trail ■ Cedarville State ForestFort Foote Park ■ Fort Washington (National) Park ■ Fran Uhler Natural Area ■ Governor Bridge Natural Area ■ Greenbelt (National) Park ■  Greenbelt Lake Municipal Park (Buddy Attick Lake Park)Lake Artemesia Natural Area ■ Merkle Natural Resources Management Area ■ Milltown Landing Natural Resources Management Area ■ Oxon Cove Park & Oxon Hill Farm ■  Patuxent Research Refuge – South Tract (National Wildlife Visitor Center)Patuxent River Park – Jug Bay Natural Area ■ Piscataway MOS Sanctuary ■Piscataway (National) Park: National Colonial Farm, Boardwalk, Wharf Road/Farmington Landing & Marshall Hall ■  Rocky Gorge Reservoir – Supplee Lane Recreation Area & Duckett DamRosaryville State Park ■ Schoolhouse Pond

Anne Arundel County: Davidsonville Park  ■ Jug Bay Wetlands Sanctuary

Charles County:  Indian Creek Natural Resources Management Area ■  Maxwell Hall Park


Bottomland DeciduousHedgerowsUpland Deciduous Lawn, Ballfields, Golf Course Agricultural Crop Fields or Fallow FieldsOld Fields, Shrubby Meadows Forested SwampFreshwater Marsh or FloodplainMud Flats (Tidal or Non-Tidal)Rivers & Streams


BeginnersHabitat Restoration ProjectHiking/Walking TrailsHistorical FeaturesNative Plant Garden or Meadow/Pollinator PlantsObservation Platform or TowerParkingPets AllowedPicnic AreaVisitor Center, Interpretive Displays, ExhibitsWater View


Audubon Important Bird AreasChesapeake Bay Gateways NetworkHistorical SitesState Natural Areas & WildlandsThe Rivers of the Western ShoreWater Trails