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Difficulty IV-V(V+)
Length 0.6 Miles
Flow Range 3.50 - 4.70 FT
Flow Rate as of: 1 hour ago 2.97 [FT] ℹ️
Reach Info Last Updated 10/03/2016 9:53 am

River Description

The Fish Ladder is the river left side channel of Great Falls along the C&O Canal towpath on the Maryland side. It is the largest of a network of small parallel channels that form Olmstead Island, carrying perhaps 10- 20 % of the total flow of the Potomac River. It was often thought to be easier than Great Falls proper, but still deserves a solid class V rating due to the difficulty of the crux and the nasty conditions of the riverbed, which shifts frequently. This channel was altered in 1892  By the Army Corps of Enginners and has been deteriorating ever since, leaving sharp rocks, chunky 'Cheese Grater' concrete, steel beams, rebar, railings from a washed out bridge and other hazards than can seriously injure an upside down boater, and tear holes in a plastic kayak. The name fishladder primarily applies to the far river left channel where the concrete slides define the crux on the run. The smaller Tight Quarters, Bridge Channel, and Olmstead channel break off to the right before the 1st slide.   The 'Back Canyon' is the narrow box canyon that splits off to the right just before the footbridge, with small rock islands and the 'Bitch Monkey" drop separating them. 

 Paddling the Fish Ladder, you are also in full view of the Park visitors, and history has proven that folks will dial 911 if they see anything other than clean lines, so don't screw up! The hazards are unfortunate but on the correct line at the correct water levels its great fun and probably won't damage your boat. All of the rapids, with the exception of the last slide, can be pre-scouted from the trail network along the C&O Canal Towpath and the footbridge leading to the Great Falls overlook. This channel collects wood  like the NSA collects phone records..... so be sure to look first.  Logjams move annually, and several riverbed changes have occured in recent years. most notably the 3rd Slide kicking harder towards The Bitch Monkey, and new rocks in the pinch of the Back Canyon. 

To learn more about the history of the Fish Ladder, read this description on the C&O Canal website.

Related reaches: Great Falls (Center Lines), Great Falls (MD Lines), and Great Falls (VA Lines).

Rapid Descriptions

Aquaduct Dam

Class - IV Mile - 0.1
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This old 5-10 foot stone dam  is easy to boof but it does dovelop into a dangerous hole at high water. the best area is 10 -100 yards from the pump house, depending where you are going. below the Dam the river splits around Olmstead and Falls Island. 

Bridge Channel (overflow)

Class - 5.1 Mile - 0.2
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also called Flood Zone, this channel splits off to the river right of the Main Fish Ladder below the aquaduct dam. Not much water goes through here until it gets above 5 feet, and there are TONS OF HUGE TREES. generally there is a way to paddle around the logjams to access the sweet slides under the Walkway but its not a good idea to paddle into this channel without a guide.

Tight Quarters

Class - IV Mile - 0.25

Tight Quarters is a more natural and relatively mellow alternative to the 1st and 2nd Slide above 4 feet, But it dumps back into the main Fishladder directly above the Back Canyon where a ferry must be executed. It  frequently collects wood but otherwise is a pleasant warm up. T.Q. splits off to river right after the Bridge Channel but before the 1st slide. The entry drop can be run either side, then there is a pool where the channels briefly rejoin between slides 1+2. Continuing on through T.Q. there is a nice 3 foot ledge to boof.  Tight Quarters ends and rejoins the main fishladder channel below the Second Slide directly above the steep stuff. A tricky ferry must be made here to avoid washing into the Back Canyon.

First Slide

Class - IV Mile - 0.3

The First Slide is fairly straightforward  fun move. Punch the hole on the left or right. Below here the Fish Ladder rejoins Tight Quarters briefly. The main channel moves quickly to the left towards the steep section

Second Slide

Class - V Mile - 0.35

The Second Slide has a boxed in hole with recirculating eddies on either side. It would be a bad place to swim because the outflow pushes toward the steepest and most continuous section of the Fish Ladder. Fortunately there is a flushy spot in the center. Get some speed going above the slide, keep your bow up, pointed straight, boof and keep your weight forward. A good place to set safety.

Back Canyon

Class - 5.1 Mile - 0.38

A  quick series of four difficult, stair-stepping drops with all the gradient of the Third and Fourth slides but no eddies in-between. The entrance is choosy but a couple of large slabs of rock fell in 2010 and made a new ledge under the footbridge just above the narrow pinch. Watch out for the table saw fin rock on the right. The next drop has A gnar pocket hole in the center and is usually boofed far right, but left goes too. Try to get left for the last drop. Then a 2 foot ledge at Fishladder confluence.  Optimal around 4.0,  High water will often deposit trees in the pinch

Third Slide

Class - 5.1 Mile - 0.4

Below the Second Slide a footbridge crosses the Fish Ladder and the current splits again around a bridge pylon. To the left of the pylon is the Third Slide of Fishladder,  and tumbling over an artificial ledge to the right is the Back Canyon. If you run the Third Slide it is critical to keep left angle as you either punch through the V wave, or take the safe line on the far left. The primary danger is getting deflected to the right over 'Bitch Monkey', a chaotic drop into the Back Canyon.  

Bitch Monkey

Class - 5.2 Mile - 0.42

This chaotic drop connects the third slide to the Back Canyon, but it has an irregular lip and a shallow landing.   It can be run well, but unfortunately it’s frequently run by accident. Formerly, there was an eddy or logjam above the slot but in recent years, rocks have shifted and much more water is rushing towards the dividing rock, and to the right over Bitch Monkey, which is now certainly in play.

Fourth Slide

Class - IV+ Mile - 0.44

After the Third Slide there is a small pool on the left above a boulder Rapid called 'Limbo' which has some fun eddies to catch but often collects wood. This leads you directly onto the Fourth slide, which is best entered in the middle pointing left. This is the shallowest slide and you will probably be scraping a little, even at high flows these days. Most people catch the big eddy on the left below the Fourth Slide and then ferry to the right, but you can also make the turn directly into The Carving Board, but there are several submerged rocks that make this a tricky race line. The Third/Fourth Slide sequence is the most technical part of the Fishladder proper.

Carving Board

Class - IV+ Mile - 0.46
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This is the junky rapid Below the 4th slide that rejoins with the Back Canyon. Very large trees tend to pile up here so keep eyes open. From the eddy below the 4th slide you'll have to pick your way through some rocks then scrape over a chunk of Concrete into a fun wavetrain with more fun eddies on the sides. These waves lead directly into the 5th slide

Fifth Slide

Class - 5.0 Mile - 0.5

This is the biggest and steepest slide and has a great horizon line overlooking S-Turn. There is a nice setup eddy above it on the right where you can boat scout the hole. From there you can peel out, come screaming down the slide, and try to punch the hole on the left or right. If you were to get stuck in the hole it would be very violent and shallow. Several boats and paddles have been broken here, and the powerful seams downstream make it an unpleasant place to swim.  A fun alternate line is to do the “Skirtless Boof” on the left and then either take out or enter the slide 1/3 of the way down. It is possible to do laps on this slide by walking up the concrete on the right bank. Paddle over to Sandy Beach and carry back up the Towpath to get back to the top.


Gage Descriptions

The Fish Ladder is most commonly run between 3.7 and 4.2, but it can be run lower and higher. Below 3.3 it is very abusive on your boat, and above 4.4 it gets pretty beefy ( levels change from year to year, as has the riverbed).
The gage 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 Gauge

NOAA Prediction for the Little Falls Gauge

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  
2020-04-05 n/a Injury Other Read More
2014-06-20 n/a Injury 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 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!


Matt Muir


Geoff Calhoun


Scott Anderson


Revision #Revision DateAuthorComment
1206892 10/03/16 Matt Muir Fixed HUC.
1206894 10/03/16 Matt Muir Numbered for sorting.
1201941 04/02/13 Geoff Calhoun updated backcanyon
1202327 06/20/13 Geoff Calhoun
1202334 06/22/13 Geoff Calhoun updated description
1202335 06/22/13 Geoff Calhoun updated location
1201691 12/02/12 Scott Anderson n/a
1202336 06/23/13 Geoff Calhoun
1201940 04/01/13 Geoff Calhoun
1201692 12/02/12 Scott Anderson Removed class rating adjustments by flow.
1202936 12/21/13 Geoff Calhoun GC
1204937 07/08/15 Geoff Calhoun GC
1202938 12/22/13 Geoff Calhoun GC
1206893 10/03/16 Matt Muir Fixed HUC.