Lock 21 — Lock 21 – Peterborough Lift Lock

Lock 21 sits at KM 145 (Mile 90.1) on the Trent Canal section of the Otonabee River, in the heart of Peterborough, Ontario. This is not a conventional mitre-gate lock — it is a hydraulic lift lock, one of only two on the entire Trent-Severn Waterway and the highest of its type in the world. The structure uses two counter-balanced water-filled troughs, each resting on a vertical ram 2.3 m7.5 ft in diameter inside a sealed cylinder. The two cylinders connect below ground through a crossover valve. When the upper trough takes on an additional 0.3 m1 ft of water — adding roughly 130 tonnes of weight — the valve opens and the heavier trough descends, hydraulically forcing the lighter trough upward. Boats are lifted 19.8 m65 ft in a single vertical movement, with vessels transiting in both directions simultaneously. The Peterborough Lift Lock was designated a Canadian National Historic Site in 1979.

Construction began in 1896 under the supervision of Richard Birdsall Rogers, Superintending Engineer of the Trent Canal, who had studied hydraulic lift locks in Belgium, England, and France before designing this structure. The site excavation and concrete work were carried out by Corry and Laverdure of Peterborough, while the Dominion Bridge Company of Montreal fabricated and erected the steel rams, presses, and caissons. The lock was formally opened on July 9, 1904. In 1985, the Peterborough Lift Lock Visitor Centre was opened in landscaped parkland adjacent to the lock. The centre included exhibits, a theatre, and a viewing area telling the story of the engineering behind the lock. The Visitor Centre is currently noted as closed on the Parks Canada lockstation listing. The Trent-Severn Waterway administrative offices are also located in Peterborough.

The transit itself is remarkably fast — the actual vertical transfer takes roughly 90 seconds, though loading and departing can extend the process to 20 minutes or more on busy days. Boaters should loop lines through the horizontal pipes inside the trough rather than cleating off, and be prepared for spectators watching from the upper viewing areas. Overnight mooring is available at the upper level only, with a maximum stay of two nights. The bottom approach has day-use dockage on the west wall for access to the Visitor Centre grounds but no overnight tie-up is permitted. Peterborough’s East City neighbourhood is roughly a ten-minute walk from the upper mooring area, providing convenient access to restaurants, groceries, and services.

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▲ Above Lock

📍 GPS: 44.3076708°N, 78.3027591°W · 353 Hunter Street East, Peterborough, Ontario, Peterborough, Ontario, ON · Get Directions ↗ · Street View ↗

For navigation, use CHS Chart #2023 — this map is for reference only and should not be used for marine navigation.

Boater Orientation Notes:

• Lock 21 is day-use mooring only — overnight mooring is NOT allowed below the lock.
• The Lift Lock Visitor Centre (Parks Canada) operates seasonally, Victoria Day to Thanksgiving — verify current status.
• East City businesses on Hunter St E are 700 m—1.2 km walk downhill from the lock.
• Rotary Greenway Trail runs from the lock south to downtown Peterborough — a pleasant, flat walk or cycle.
• East City Coffee Shop is CASH ONLY — ATMs available nearby on Hunter St.

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Last Updated: March 18, 2026

The famous one. Picturesque, heavily marketed, modern marvel of engineering — all that stuff is well-documented elsewhere. From a skipper’s perspective, there’s actually not much to talk about. No current to deal with. You might get some wind swirling around on both the lower and upper sides, but that’s about it. ONE THING TO WATCH — AND IT COULD RUIN YOUR DAY: when they lower the chamber down to you, there’s a wall that pivots toward you and falls into the water before you can enter. The light won’t turn green until that wall is fully down in the water. DON’T APPROACH until the wall is down and the light is on. It’s the kind of thing you could see someone running into or getting in the way of if they’re not paying attention. Pay attention to the lights, hold your position until cleared, and enjoy the view — you’re not going to see another lock like this on the system.

Weather data for navigation planning purposes only. Always check Environment and Climate Change Canada’s official marine forecast before making operational decisions. weather.gc.ca ↗