Potomac River near Washington DC (Little Falls)

1. 17.00 ftWater overflows the overlooks at Great Falls National Park and approaches the lower level of the visitors center. Most of the C&O Canal towpath downstream of Pennyfield is flooded. There is approximately a foot of water in the clubhouse on Sycamore Island.
2. 16.00 ftWater reaches the clubhouse on Sycamore Island.
3. 15.00 ftMost of the C&O Canal towpath from Pennyfield downstream is flooded.
4. 14.00 ftSignificant portions of the C&O Canal towpath are flooded. The Blockhouse Point Park is flooded. Water reaches the retaining wall at Overlook 1 at Great Falls National Park but does not overtop it.
5. 12.00 ftThe C&O Canal overflows at the Great Falls Tavern. Water covers the towpath in many areas.
6. 11.50 ftWater covers the towpath in multiple spots between the Washington Aqueduct Dam and Pennyfield Lock, mileposts 15 to 19 on the C&O Canal.
7. 11.00 ftWater covers the towpath between Swains Lock and Pennyfield Lock, mileposts 17 to 19 on the C&O Canal.
8. 10.00 ftWater begins to overflow the banks into low lying areas on the Maryland side of the river near Little Falls. Water begins to enter the canoe shed at Sycamore Island.
9. 9.00 ftSeveral trails on both sides of the river between Great Falls and the Chain Bridge are flooded and will be closed.
10. 7.00 ftUpper portions of the River Trail at Great Falls National Park begin to flood and will be closed.
11. 5.50 ftWater reaches the top of the ferry landing for Sycamore Island. Ferry service to the island will likely be suspended.
12. 5.00 ftPortions of the Potomac Heritage Trail begin to flood. Water begins to affect portions of the Billy Goat Trail between Great Falls and Carderock. These trails will be closed.
13. 4.50 ftThe river reaches danger level for boaters, as defined by the State of Maryland. Conditions for boating will be extremely hazardous.
14. 3.50 ftThe river reaches caution level for boaters, as defined by the State of Maryland. Fast moving water and changing currents will be experienced.

Chance of flooding, September to November

The three-month chances are the River Forecast Centers’ long-range flood outlook, issued August 28, 2026.

Most recent crests

• May 16, 2025: 11.73 ft
• May 9, 2022: 10.16 ft
• December 17, 2018: 11.56 ft
• September 29, 2018: 11.01 ft
• September 11, 2018: 10.85 ft
• June 5, 2018: 12.38 ft
• May 18, 2014: 11.70 ft
• October 31, 2012: 10.33 ft
• September 9, 2011: 9.78 ft
• May 20, 2011: 11.30 ft

• UpstreamPotomac River at Edwards Ferry
• DownstreamPotomac River at Georgetown / Wisconsin Ave
• Dead Run at McLean
• Rock Creek at Joyce Road in Washington
• Four Mile Run
• Rock Creek at Sherrill Drive/DC
• Tripps Run
• Rocky Run at Tysons Corner (Pulte/McLean Regional Pond)
• Difficult Run at Great Falls

Forecasts by the Middle Atlantic River Forecast Center. Forecasts are issued routinely year-round. Stage may be affected by ice.

Stage, flood stages, impacts and crest history from NOAA’s National Water Prediction Service. Streamflow and the daily record from the U.S. Geological Survey.