Lock 45 Port Severn is the moment every Great Loop cruiser has been working toward since entering the Trent-Severn Waterway at Trenton. Passing through this final lock means completing the 386 km Canadian inland passage and emerging into Georgian Bay — open water, open sky, and the vast horizon of Lake Huron ahead. For many Loopers, the quiet hand-cranked drop into the Severn River below the dam marks the emotional high point of the entire journey: the canal is behind you, and the North Channel beckons. Learn more at AGLCA: https://www.greatloop.org/
Lock 45 Port Severn is the final lock and western terminus of the 386 km 240 mile Trent-Severn Waterway. Situated at kilometre 387.1 on the Severn River where it meets Georgian Bay, this hand-operated lock marks the point where the sheltered canal system ends and open Great Lakes navigation begins. Vessels exiting Lock 45 enter Georgian Bay — part of Lake Huron and the start of open water passage toward the North Channel, Killarney, and the upper Great Lakes. The lock sits within the Township of Georgian Bay in Simcoe County, at the community of Port Severn, and is the smallest lock on the entire system. Its chamber dimensions of 25.6 m × 7.0 m 84 ft × 23 ft are what ultimately determine the maximum vessel size that can transit the full waterway from Lake Ontario to Georgian Bay. Parks Canada
Contracts for Lock 45 were awarded in 1914 as part of a plan to build three locks connecting the Severn River to Georgian Bay at Port Severn, Big Chute, and Swift Rapids. The outbreak of World War I created an immediate shortage of manpower and resources, and Lock 45 — which was nearest to completion — was finished as a smaller, “temporary” structure around 1915. That temporary lock has never been replaced and remains in active service more than a century later, still operated by hand in the same manner as when it was built. The Parks Canada visitor centre adjacent to the lock houses displays on the history of the Trent-Severn Waterway system, including models of other famous lift locks around the world, and is operated by TrentSevern.com as a non-profit initiative. The lock grounds include camping areas, picnic facilities, washrooms with potable water, and overnight mooring for vessels up to a maximum stay of two nights. Parks Canada CHS CEN309
Boaters departing Lock 45 should prepare for a significant transition from canal to open water. The navigation channel below the lock passes under Highway 400 with a restricted channel width and 9.1 m 30 ft bridge clearance, and currents of approximately 2 knots run between the lock and the highway bridge — stronger during spring freshet or after heavy rain. The channel through Little Lake toward Georgian Bay is marked with more than ten buoys in rapid succession, and depths are influenced by Georgian Bay wind conditions that can add or subtract a foot of water from the already shallow passage. Six marinas operate in the immediate Port Severn area, with fuel (gasoline and diesel), pump-out, repair services, and marine supplies available at Starport Severn and several adjacent facilities. Port Severn village offers motels, restaurants, a liquor store, post office, and basic provisions, though the nearest hospital is at Midland, approximately 21 km 13 miles away. CHS CEN309 TSW DB
| Official Name | Lock 45 — Port Severn Parks Canada |
| Lock Number | 45 |
| GPS Coordinates | 44°48′14.8″N, 79°43′13.9″W 44.8041, −79.7205 Parks Canada |
| Street Address | 175 Port Severn Rd N, Port Severn, Ontario Parks Canada |
| KM Marker | 387.1 km Mile 240.6 Parks Canada |
| Region | Township of Georgian Bay, Simcoe County |
| Water Body | Severn River — Georgian Bay (Lake Huron) |
| CHS Nautical Chart | #2029 CHS |
| Nearest Municipality | Port Severn, Ontario |
| Historic Construction | Contracts awarded 1914; completed c. 1915 as temporary wartime lock Parks Canada |
| Lock Phone | (705) 538-2586 Parks Canada |
| trentsevern@pc.gc.ca |
| Parameter | Metric | Imperial |
|---|---|---|
| Lock Number | 45 | |
| Average Lift | 3.66 m | 12 ft |
| Chamber Length | 25.6 m | 84 ft |
| Chamber Width | 7 m | 23 ft |
| Maximum Draft System-wide | 1.8 m | 6 ft |
| Gate Type | Hand-operated | |
| VHF Channel | Channel None | |
| Operating Season Parks Canada | Mid-May to mid-October | |
| Max Mooring Period Parks Canada | 2 nights | |
| Permit Required | Yes — 1‑888‑773‑8888 or parks.canada.ca | |
| Electricity | ✗ Not Available | |
| Potable Water | ✔ Available | |
| Pump-Out | ✗ Not Available | |
| Operator | Parks Canada — Environment and Climate Change Canada | |
| Lock Phone Parks Canada | (705) 538-2586 | |
▲ Above Lock
▼ Below Lock
▼ Below Lock
📌 ~10 km from lock
📌 ~30 km from lock
🌊 Depths: 10/20 ft (approach/dock)
📌 ~35 km from lock
🌊 Depths: 10/10 ft (approach/dock)
📌 ~40 km from lock
📍 GPS: 44.8042°N, 79.7208°W · 175 Port Severn Rd N, Port Severn, Ontario, Township of Georgian Bay, Muskoka, Ontario, ON · Get Directions ↗ · Street View ↗
For navigation, use CHS Chart #2029-1 — this map is for reference only and should not be used for marine navigation.
☎ Coldwater Taxi — (705) 686-3265 — Based in Coldwater (~15 min away). Call ahead to arrange pickup. Limited availability — not always immediate.
No Uber/Lyft available in Port Severn. No public transit serves the village directly.
Boater Orientation Notes:
- Lock 45 is the western terminus of the TSW (Mile 240.5) and the smallest lock on the waterway (25.6 m) — hand-operated, controls maximum vessel size for the entire system.
- Walkable amenities are limited to an ~800 m stretch of Port Severn Rd N — no pharmacy, hardware, or full grocery within walking distance.
- The Grill at Bush’s Marina (~100 m) and The Icebreaker floating sweet shoppe are directly beside the lock — boat-up accessible.
- Driftwood Cove Marine Resort (~500 m) has coin laundry, showers, gas, marine store, and restaurant — closest laundry option for boaters.
- After exiting Lock 45, buoy colours CHANGE — reds to STARBOARD exiting Port Severn. Narrow channel — follow charts carefully and stay alert.
🛒 Grocery
| Name | Directions | Phone | Rating | Distance | Access |
| LCBO 🔗 | Let’s Go! | (705) 538-2500 | ⭐ 3.9 | ~800 m | Walkable |
| Port Severn General Store 🔗 | Let’s Go! | (705) 538-1789 | ⭐ 4.0 | ~600 m | Walkable |
🍴 Restaurants
| Name | Directions | Phone | Rating | Distance | Access |
| Lighthouse45 Restaurant (Rawley Resort) 🔗 | Let’s Go! | (705) 538-2272 | ⭐ 4.0 | ~800 m | Walkable |
| The Galley (Driftwood Cove Marine Resort) 🔗 | Let’s Go! | (705) 538-2502 | ⭐ 3.8 | ~500 m | Walkable |
| The Grill (Bush’s Marina) 🔗 | Let’s Go! | (705) 538-1234 | ⭐ 3.9 | ~100 m | Walkable |
| The Icebreaker (Bush’s Marina) 🔗 | Let’s Go! | (705) 538-1234 | ⭐ N/A | ~100 m | Walkable |
| Exit 156 Port Severn Restaurant 🔗 | Let’s Go! | (705) 538-2941 | ⭐ 4.3 | ~2.5 km | Short Drive |
🏛 Local Interests
| Name | Directions | Phone | Rating | Distance | Access |
| Gloucester Pool Anchorage | Let’s Go! | N/A | ⭐ N/A | By boat from Lock 45 | Walkable |
| Lock 45 Visitor Centre 🔗 | Let’s Go! | N/A | ⭐ 4.5 | On-site | Walkable |
| White’s Falls 🔗 | Let’s Go! | N/A | ⭐ 4.3 | ~8 km | Short Drive |
🔧 Support & Services
| Name | Directions | Phone | Rating | Distance | Access |
| Bush’s Marina 🔗 | Let’s Go! | (705) 538-2378 | ⭐ 3.9 | ~100 m | Walkable |
| Driftwood Cove Marine Resort 🔗 | Let’s Go! | (705) 538-2502 | ⭐ 4.0 | ~500 m | Walkable |
| Rawley Resort Marina 🔗 | Let’s Go! | (705) 538-2272 | ⭐ 4.0 | ~800 m | Walkable |
| Starport Marina | Let’s Go! | (705) 538-2975 | ⭐ 3.8 | ~1.2 km | Walkable |
| Esso Gas Station (propane and convenience) | Let’s Go! | (705) 538-2941 | ⭐ 4.7 | ~2.5 km | Short Drive |
Last Updated: March 18, 2026
Post-Kirkfield: red and green channel buoys are on opposite sides from the lower system. Red-right returning applies southbound, not northbound. Verify with CHS Chart #2029-1 before transiting. CHS CEN309
Shoal locations, rock hazards, and current data for Lock 45 – Port Severn are being compiled from CHS CEN309 and current Notices to Mariners. Check notmar.gc.ca for active advisories. CHS
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 ↗