Difficulty V+ at this flow (V+ normally)
Length 1 Miles
Flow Range 3.30 - 3.95 FT
Flow Rate as of: 52 minutes ago 3.84 [FT] ℹ️
Reach Info Last Updated 04/29/2019 3:07 am

River Description

Great Falls of the Potomac River is a major set of rapids located about 15 miles upstream of Washington, DC. The main Falls lines drop fifty feet in one-tenth of a mile, creating a Class V+ set of waterfalls. In addition, a portion of the river flows around Olmstead Island in a channel called the Fish Ladder (additional channels flow at higher water).

Center Lines (Grace Under Pressure/ Fingers) It is a spectacular cataract with some sweet lines, but  when running it - you are on the fringe of a massive channel surrounded by deadly sieves, huge holes,  and treacherously slippery rocks, and if you don't know it - its easy to get disoriented. There were major changes in Spring 2018 so everyone should scout because the ideal flows have changed. It is not obvious how to get out to scout if you haven't been there before, a guide is mandatory. Even the sleeper pourover in the class 3 approach rapid above the falls can dish out a beating at these levels, and all the other drops to the river left of Grace Under pressure and river right of Pummel are extremely seivey and dangerous. A substantial amount of the flow goes towards the Subway sieve or into the Maryland Lines, http://www.americanwhitewater.org/content/River/detail/id/5553  which will be stompy. Swimming anywhere near the Center lines is a life threatening mistake that usually requires an elaborate rescue in full public view. There have now been 2 fatalities here of experienced kayakers who had run the lines before, most recently in July 2013. http://www.americanwhitewater.org/content/Accident/detail/accidentid/3743/.  Know your limits out here and don't come without a guide and very experienced friends. Center lines is an intricate maze that requires  A LOT of scouting, and choosing the wrong channel, or swimming could kill you and put access at risk for everyone. Please be careful and always have a safety plan, this is serious class 5.



Paddlers have known about Great Falls as long as there has been whitewater kayaking. Many of the features -- such as the Spout, the Fingers, the Fish Ladder -- have names that predate paddling, in some cases by hundreds of years. But it was not until paddlers started running waterfalls regularly in the 1970s that paddlers began to seriously consider running the Falls. The first descent of Great Falls was made in 1975 by local experts Tom McEwan and Wick Walker, with the second descent by Steve McConaughy and Great Falls National Park Ranger Bill Kirby. The Center line was pioneered in the mid- 1980's by Paddlers like Eric Jackson and Chris Good.

River Signals and Helicopters

The Park Service patrols the Potomac with a helicopter most summer weekends. In an effort to minimize confusion, the helicopter pilots are trained to recognize three signals from paddlers.
Everything OK - Tap the top of your helmet with one hand.
Emergency - Wave both arms together over your head (like jumping jacks), holding brightly colored objects if possible.
Need Medical Attention - Form an X with arms or paddles.
Don't signal the helicopters unless you need them! And if being inspected, be sure to give the OK sign if you don't need assistance. Sometimes hikers call in "emergencies" that aren't actually emergencies.

Rapid Descriptions

Grace Under Pressure

Class - 5.1 Mile - 0.4

Arguably the toughest standard line in Great Falls and different as of 2018. Skirt to the right of the top hole, then boof off the right side of the 12' waterfall. The landing is chaotic, so Eddy out right, immediately on the left, or continue down to the Ledges. A swim anywhere in this area is potentially fatal due to what lies downstream. 

The next drop over, Sliding Boad (Class 5.2) crashes into the bottom of Grace and was rarely run due to  horrible sieves on the left. As of 2018 this rapid carries more flow and is temping when Grace is too low

The Ledges

Class - IV+ Mile - 0.45

A short sequence of 3-5' ledges and slots. They're not that hard, but if you lose control or get disoriented things can go downhill in a hurry. The center- right channel is the traditional double boof line and should be finished by landing right into the swirly pool above the Fingers. The right-most option is called the Angel Slot and is more difficult and committing. To the left, where you DON'T want to go, next to Charlie's Hole (MD side) is an inviting channel called Hollywood Boulevard that funnels toward Twist n' Shout, and the deadly Subway - this should not be run.

The Fingers

Class - V Mile - 0.5

Also known as the Streamers.  Five slots that can look alike from above, with serious consequences for choosing the wrong one. From river left to right, they are:

Twist and Shout (the Thumb) (Class 5.3) - A narrow, twisty drop with high piton potential. ugly and rarely run, but way better than Subway!.

Subway (6/NR) - A steep double drop with a sieve at the top and a cave at the bottom. This drop has been run accidentally a couple times but has killed two swimmers. Most recently an elite female paddle drowned here in 2013: http://www.americanwhitewater.org/content/Accident/detail/accidentid/3743/  It also  Took the life of an experienced class V kayaker in 2004 who swam into it.  Avoid at all costs. swimming into it is 100% fatal. safer lines are to the right.

The Middle Finger (Class 5.0) - this is the standard line. Pretty straight forward 20' drop but the entrance is only a couple feet from Subway. Calm green water leads into a 4' diameter slot. angle straight.  you slide down  8 feet then lefty boof  about 12' 

The Ring Finger aka Flatliner (Class 5.1) - Shallow landing zone. rocks underneath and to the right. Higher water line. Run out of the eddy just left of center boofing off the nub.  Miss the boof and you’re [censored]. A well known boater ran it too low, broke ribs and ruptured his spleen here. Google: epic fail

The Pinky Finger aka Angel Hair (Class 5.2) - Tricky entrance (angel slot or ferry in). Lands in a boily cauldron between a sheer rock wall and an undercut boulder. If you swim in the pocket, there's a small underwater ledge against the Flake that you can stand on while awaing a rope and figuring out your next move.

Make SURE you know which slot to take. there are no arrows painted on the rocks and the wrong choice at the wrong level could be fatal.


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Geoff Calhoun
1 year ago

The Center Lines has changed in the Spring of 2018. the ideal flows are now different, its not being run low as was previously possible. There is less water in Grace Under Pressure, and while the drop is the same, the entrance and landing are different.

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angela baldo
7 years ago

Here is a functional link to a story about the kayaker who swam into Subway in 2004 http://www.washingtonpost.com/wp-dyn/articles/A62644-2004Oct25.html (link on the main page is broken)

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Scott Anderson
11 years ago

Thanks for your input. As the streamkeeper, I have to use my best judgment when listing river data. The solutions aren't always ideal, but I will try to explain my rationale with regard to gradient. "Please explain how a 1 mile stretch of river can have average gradient of 100 fpm and maximum gradient of 500 fpm." The river drops 100 feet between the put-in and the take-out, which are 1 mile apart. So the average gradient is 100 fpm. However, the heart of the run drops 50 feet in 0.1 miles, for a maximum gradient of 500 fpm. "Maximum gradient figures cited 'up top' should always be computed across a full mile, otherwise they are meaningless." Says who? There is no standard way to calculate gradient. Leland Davis calculates gradient mile by mile in NC Rivers & Creeks, but Stafford and McCutcheon use terms like "200 fpm," "200 fpm action," and "200 fpm crux" in The New Testament. Which is right? Great Falls is a park and huck, so calculating gradient mile by mile would be meaningless. Nobody puts in above Great Falls unless they plan on running it. They're not there for the paddle in and the paddle out. The only section that counts is Great Falls itself, which is 500 fpm. I would put "500 fpm crux" if I could, but the AW page builder doesn't give me that option. Furthermore, removing the 500 fpm maximum gradient from 'up top' could mislead people into thinking Great Falls is no steeper than the Upper Yough. "If you wish to convey that some shorter portion has steeper gradient, you may express that within the text of the description..." The description includes the following statement: "The main Falls lines drop fifty feet in one-tenth of a mile." The reason I include the maximum gradient up top is that nobody reads the description.

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11 years ago

I was out here the other day to run the Spout. The temperature was supposedly about 93 degrees, but, even though I arrived on Flake Island after sunset, the heat was very, very oppressive. Sitting down to rest did not help, as the rocks were super-heated by the sun to around 120 degrees. I was rapidly becoming seriously dehydrated and probably lost about 30 percent of my strength before putting in to run the rapid. This rapid should probably not be scouted during daylight in the summer. So watch out for the summer heat; I came close to having a heat stroke!!! Also, the water temperature is close to 100 degrees, too, so it provides close to zero cooling.

Gage Descriptions

The Center lines are the only part of the main falls that can't be run at summer low water. As of 2018, Minimum for Grace was nearly 3.5. The rapid next door carries more of the flow now. Above 3.8 the landing off Grace gets rowdier and there's very little time to recover if something goes wrong.

The gauge is located at Little Falls (aka Brookmont) Dam, where the river is very wide.  Consequently, an inch on the gage can translate to a foot at Great Falls.  The gage is also 8-9 miles downstream, so if the river is rising or falling rapidly there could be a discrepancy between the gage reading and the actual level.  Scout the rapids visually if there is any doubt.  (You were going to do that anyway, right?)

USGS Potomac River / Little Falls Gage

NOAA Prediction for Little Falls Gage

Directions Description

Most people park at Great Falls (MD) to run the Falls. There is a $5 fee per vehicle to enter the park, or you can buy an annual pass for $20. The MD pass is honored on the VA side and vice versa. You can get directions by typing the address of the Great Falls Tavern Visitor Center into Google Maps or Mapquest:
11710 MacArthur Blvd.
Potomac, MD 20854
No shuttle is necessary. When you finish running the Falls, continue downriver and take out at Sandy Beach. Then walk back to your car via the Towpath.

Date Flow Result Factor  
2013-07-11 Medium Fatality Other Read More



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Upper Yough Access Guidelines and Fundraiser

Charlie Walbridge

At Maryland's Upper Yough, one of the country's finest whitewater runs, American Whitewater has been maintaining the Sang Run Access for the past 20 years. With the 4th of July weekend coming up, a quick reminder that we are guests of the Town of Friendsville when we take out. In addition changing clothes discretely ad behaving respectfully, please observe social distancing during the pandemic. Garrett County has a low infection rate, and a mask when patronizing local businesses is the norm. We are also beginning our annual fundraiser to pay the expenses American Whitewater has at Sang Run. Out goal is $1,000, and we have already received $160. The Fee Box at Sang Run is still closed due to vandalism. We suggest $20 for the full season; $5 for one weekend. Please donate on line, or use the donation jar at the Wilderness Voyageurs shop at the takeout. Please go to https://www.americanwhitewater.org/content/Membership/donate/? and put "Upper Yough Access" in the comment box.

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Don Millard - AW Super Upper Yough Access Volunteer!

Charlie and Sandy Walbridge

American Whitewater super-volunteer Don Millard has been taking care of the Sang Run and Friendsville Access Areas on Maryland's Upper Youghioghenny River for the past several years. This bulds on a 2003 agreement between American Whitewater and Maryland State Parks, which owns the property. This year he rebuilt the change house and porta-pot shelter, set AW's sign back up, filled in potholes, and mowed acres of grass. He not only did the work, he donated the materials and machine time! This work givezs AW strong ties to the community (the place is also a fishing access) and local park managers. Also, thanks to him, boaters are not faced with a $5 access fee at both ends! Please remember, the pandemic is still on. Be smart. If you use the porta-pot, wash your hands or use sanitizer!

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Kayaker Killed Running the Potomac's Great Falls: July 11, 2013

Charlie Walbridge

Shannon Christy, a charismatic young paddler, was killed in Great Falls of the Potomac River on July 11th, 2013. After bailing out below Grace Under Pressure, one of the center chutes, she washed over the notorious "Middle Finger" drop into the Subway, a deadly sieve. There is a full write-up of this fatality in the AW Accident Database. The photo shows Steve Fisher and Jason Beakes during the difficult body recovery.

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2010 Potomac Fest - July 10-11 (MD/VA)

Kevin Colburn

Come see American Whitewater at this year's Potomac Fest, July 10 and 11 in Great Falls, MD/VA!  Just minutes from the Nation's Capital, the 20th Annual Potomac Whitewater Festival will be two days of fun events organized to delight beginners, experts and spectators alike.


Matt Muir


Geoff Calhoun


Tony Allred Jr


Revision #Revision DateAuthorComment
1200616 09/07/11 Matt Muir Added 2nd state; reordered.
1201693 06/23/13 Geoff Calhoun updated description
1202338 06/23/13 Geoff Calhoun
1202386 07/15/13 Geoff Calhoun
1202625 08/26/13 Geoff Calhoun GC
1202955 12/29/13 Geoff Calhoun accident link
1202956 12/29/13 Geoff Calhoun be safe
1202959 12/30/13 Geoff Calhoun links
1202960 12/30/13 Geoff Calhoun description
1210304 09/02/18 Geoff Calhoun GC
1206889 10/03/16 Matt Muir Fixed HUC.
1210300 09/01/18 Geoff Calhoun gc
1210303 09/02/18 Geoff Calhoun GC
1210709 12/14/18 Tony Allred Jr 12-15-2018 - cleanup
1212071 04/29/19 Tony Allred Jr updated image position
1194808 08/13/20 n/a n/a