Great Falls is a 47-foot Class V+ rapid on the Potomac River in Montgomery County, Maryland, where the river breaks over the fall line in a chain of drops around rock islands before squeezing into Mather Gorge. On the Maryland side the falls sit in Chesapeake and Ohio Canal National Historical Park, with a boardwalk to an overlook on Olmsted Island.
The falls
The Potomac splits into several plunging and cascading channels here. Topographic analyses measure the height at 47 feet, contrasting with long-quoted figures of 76 feet measured as a series of 20-foot falls, while whitewater surveys record about 50 feet across 0.1 mile on the main drops. The bedrock is metamorphic schist and gneiss roughly 750 million years old.
The Maryland lines run Class V+ over a 0.4-mile reach, usually run at low water and monitored on the Little Falls Pump Station gauge near Washington. Paddlers put in on the Maryland shore above the aqueduct dam, or below it at higher levels; landing on or launching from the Olmsted Island boardwalk is not allowed. The Horseshoe is marked as a portage and hazard, and the carry back up at the Flake is slippery when wet. Sandy Beach below the falls serves as the usual exit, with a walk back along the towpath.
Getting there
Park at the Great Falls Tavern Visitor Center in Potomac, off MacArthur Boulevard. From the tavern it is about 0.25 mile to the boardwalk and another 0.25 mile across it to the overlook, roughly 1 mile round trip on an easy, wheelchair-accessible route. The tavern area is the only fee site in the park: $20 per private vehicle, $15 per motorcycle, $10 per person on foot or bicycle aged 16 and older, or $35 for an annual park pass; America the Beautiful passes are accepted, and payment is card only. As of September 2026, the access road, parking, boardwalk and all three sections of the Billy Goat Trail remain open.
When to go
The falls run year-round. Section A of the Billy Goat Trail often closes when the river floods. Paddlers are advised to run the falls in the morning, before the park fills with visitors.
On site
Visitors must stay on the boardwalk; walking onto Olmsted Island is illegal, and dogs are not allowed. Cell service is unreliable. Park safety records show that 51 percent of river injuries in the Potomac Gorge are fatal, most involving swimmers, waders or people who slipped off rocks; swimming and wading are illegal, with fines of $200 or more. Boaters must wear life jackets and kayakers helmets. A kayaker died on the Virginia lines below the main drops on May 3, 2026.
History and name
The falls are also called the Great Falls of the Potomac. The Chesapeake and Ohio Canal was built along the Maryland side in the early 19th century, and Great Falls Tavern served canal travelers as a hotel from 1831.
Nearby
The Spout is about 0.5 mile away, Calico Rapids is about 3.1 miles away, Stubblefield Falls is about 3.9 miles away, and Little Falls is about 8.6 miles away.
Distances are straight-line.