Patapsco Valley State Park

Patapsco Valley State Park, stretching 32 miles along the Patapsco River through Baltimore and Howard Counties, is Maryland’s oldest and most-visited state park — 16,000 acres of forested river gorge, waterfalls, historic railroad infrastructure and river-bottom trails winding through one of the most dramatically scenic river corridors in the mid-Atlantic, just minutes from the Baltimore metropolitan area.

The park’s five developed areas (Avalon, Orange Grove, Hollofield, Hilton and McKeldin) each offer distinct character — from the dramatic Patapsco River gorge at Avalon with its swinging bridge and river cascades, to the wide-open McKeldin area at the river’s headwaters. The historic Thomas Viaduct (1835 — the oldest multiple-arch stone railroad bridge in continuous use in the United States) crosses the Patapsco near Relay, connecting the park to Baltimore’s industrial heritage. Patapsco Valley State Park is a treasured natural and historical icon of Maryland.

Patapsco Valley State Park offers hiking on over 200 miles of trails through the river gorge (the Cascade Falls Trail, the Ridge Trail, the River Trail and many connecting loops — terrain ranging from easy riverside walks to steep, rocky gorge climbs), mountain biking on dedicated trails (the McKeldin area and the Hollofield area have excellent trail networks), fishing the Patapsco River (stocked trout in spring, smallmouth bass, catfish and sunfish year-round; the river is a popular fishing destination), picnicking at the developed areas (Avalon, Hollofield and McKeldin have shelters and picnic areas), seasonal camping at the McKeldin campground, and historic exploration (the Thomas Viaduct, the historic ruins of the Bloede Dam — the first underwater power-generating hydroelectric dam in the US, now a historic site — and the historic mill communities). The Avalon gorge trails, the Cascade Falls and the river fishing are the signature draws.

Spring (April through early June) is the finest season on the Patapsco — the wildflowers bloom in the gorge (Virginia bluebells, trout lily, trillium and jack-in-the-pulpit carpet the river bottom in April), the trout stocking draws anglers, the spring warblers fill the gorge canopy, and the Patapsco River runs full and dramatic. Fall brings the gorge forest color — the steep gorge walls turn gold and orange, framed by the river below. Summer is pleasant (the gorge is shaded and cooler than the surrounding suburbs) and busy. Spring for the wildflowers and warblers, and fall for the color, are the highlights.

Patapsco Valley State Park encompasses one of the most historically layered river corridors in Maryland — the valley was the site of early colonial mills (the Ellicott family established their famous Ellicott’s Mills flour-milling complex in the 1770s, now the city of Ellicott City adjacent to the park), the route of the Baltimore and Ohio Railroad (the first commercial railroad in the US, which followed the Patapsco gorge out of Baltimore), and the site of the Bloede Dam (1906 — the first underwater power-generating hydroelectric dam in the US). The park was established in 1907. Periodic severe floods (most recently Tropical Storm Agnes in 1972 and Hurricane Eloise in 1975) have dramatically reshaped the gorge. The park preserves the combined natural and industrial heritage of the Patapsco Valley.

The Patapsco Valley cuts through the Maryland Piedmont, exposing ancient Precambrian and Paleozoic metamorphic rocks (schists, gneisses and quartzites) in the gorge walls — some of the oldest rocks exposed at the surface in Maryland. The river has incised a dramatic gorge through the resistant Piedmont terrain, creating the steep valley walls, the river cascades and the rocky stream bed that characterize the park. The Thomas Viaduct near Relay (1835) is built directly on the Patapsco schist. The Piedmont bedrock, the river incision and the steep gorge topography created the dramatic river-gorge landscape of the park.

The Patapsco Valley gorge supports a rich mid-Atlantic wildlife community — white-tailed deer, red and gray foxes, great blue herons (nesting colony in the park), bald eagles (year-round along the river), osprey (nesting in season), wood ducks, belted kingfishers, pileated woodpeckers, and a diverse spring warbler migration through the gorge corridor. The Patapsco River supports smallmouth bass, stocked trout, catfish and sunfish. The gorge’s mix of mature forest, river bottom and rocky bluffs creates diverse habitat that supports a wide variety of wildlife within minutes of downtown Baltimore.

Patapsco Valley State Park protects 16,000 acres of forested Piedmont river gorge in one of the most densely populated regions of Maryland — an exceptional and irreplaceable block of mature forest and river-bottom habitat in the Baltimore metropolitan area. The Patapsco River is a Chesapeake Bay tributary; protecting the river’s water quality is a direct contribution to Bay health. Invasive plants (Japanese stiltgrass, garlic mustard, multiflora rose) are significant management challenges in the gorge. Flood disturbance and the recovery of the river-bottom forest are ongoing ecological dynamics. Protecting the gorge forest, the water quality and the wildlife corridor sustains this vital urban-edge park.

Patapsco Valley State Park holds a treasured place among the icons of Maryland — Maryland’s oldest and most-visited state park, the 32-mile river gorge corridor through the Baltimore metropolitan area, the route of the first commercial railroad in the US, and the site of the historic Ellicott’s Mills milling complex (now Ellicott City). The combination of dramatic gorge scenery, historic industrial heritage and accessible nature just minutes from Baltimore makes Patapsco exceptional. It is a cherished natural and cultural icon of Maryland.

Patapsco Valley State Park has five developed areas along the 32-mile park corridor. The Avalon area (the most popular, with the Cascade Falls and swinging bridge trails) is at 8020 Baltimore National Pike in Ellicott City — off U.S. Route 1 south of Ellicott City. The McKeldin area (campground and headwaters trails) is in Marriottsville off MD Route 144. All areas have parking; a per-vehicle Maryland state park fee applies (or annual pass). Ellicott City (adjacent to Avalon — a charming historic town with restaurants and shops) has full services. Check Maryland DNR for current fees, trail conditions and campground reservations before visiting.

Maryland DNR manages Patapsco Valley State Park. Invasive plants are among the most significant conservation challenges — volunteers are essential for garlic mustard, Japanese stiltgrass and multiflora rose control; check Maryland DNR for volunteer events. Flooding periodically damages trails and infrastructure; closures are common after heavy rain events. Protect the river and Chesapeake Bay by packing out all trash and never dumping anything in or near the river. Eagles and herons nest in the park — respect all posted nesting buffer areas. The recovering gorge forest, the river water quality and the wildlife corridor are the key conservation priorities.

The Patapsco River can rise quickly and dramatically after heavy rain — never cross the river on foot when it is flowing fast or above the knee, and heed all park closure signs after storms. The gorge trails are rocky and uneven; wear sturdy footwear with good traction (especially near the river cascades, where the rocks are slippery). The trails can be muddy and slippery after rain. Ticks are abundant year-round (Lyme disease is endemic in Maryland); check thoroughly after any hike. In Ellicott City the adjacent downtown area has flooded catastrophically in recent years — the park is separate and safe, but respect any urban flood warnings. Respect the rising river, the rocky gorge trails and the ticks.

Maryland state park entrance fee per vehicle (or annual pass; check Maryland DNR for current rates). Stay on designated trails. Fishing requires a Maryland license (trout stocking areas may have additional rules; check Maryland DNR). Pets on leash at all times. No swimming in the Patapsco River (posted in most areas; the river currents are hazardous). Mountain biking on designated bike trails only. McKeldin campground requires advance reservation. Check Maryland DNR for current conditions, trail closures and fee schedule before visiting.

The historic town of Ellicott City (adjacent to the Avalon area — one of the finest 19th-century mill towns in the mid-Atlantic, with restaurants, shops and the B&O Railroad Museum at Ellicott City Station), the city of Baltimore (20 minutes east — the Inner Harbor, Fort McHenry, the Maryland Science Center), the B&O Railroad Museum in Baltimore, and the Howard County and Baltimore County suburbs define the region. Patapsco Valley State Park anchors the nature experience of the Baltimore metropolitan area, offering a genuine river-gorge forest experience just minutes from the city.

Walk the Avalon area’s Ridge Trail and River Trail loop (about 4 miles) for the finest Patapsco gorge experience — the steep gorge views from the Ridge Trail, the Cascade Falls, and the river bottom through the ancient sycamores are extraordinary, and the swinging bridge crossing is a classic. Come in late April for the Virginia bluebells blooming on the river flats — the blue carpet of bell-shaped flowers along the Patapsco is one of the finest wildflower displays near Baltimore. Visit Ellicott City for a meal or coffee after the hike for a perfect combination of nature and history. Fish the Patapsco in April and May during trout stocking for an accessible mountain-stream fishing experience in the city’s backyard.