The St. Marys River is the sole natural outlet of Lake Superior, carrying its entire outflow approximately 75 miles southeast to Lake Huron. At Sault Ste. Marie, the river drops about 21 feet through the rapids and the Soo Locks — one of the busiest lock systems in the world. The river passes through several wide lake-like sections including Munuscong Bay and Potagannissing Bay before entering Lake Huron near Drummond Island.
Ice fishing is popular on the St. Marys River's bays and sheltered backwaters, where ice forms reliably in a typical UP winter. The main shipping channel and areas with strong current are dangerous and may not freeze safely — current undermines ice thickness in ways that aren't visible from the surface. Always check local reports and avoid areas near the navigation channel.
What fish are in the St. Marys River?
Where is the St. Marys River?
Can you watch freighters on the St. Marys River?
How many boat launches are on the St. Marys River?
Can you ice fish the St. Marys River?
Can you kayak the St. Marys River?
Are there campgrounds on the St. Marys River?
Is the St. Marys River safe for swimming?
Is the St. Marys River the same as the Soo Locks?
The St. Marys River is the 75-mile connecting waterway between Lake Superior and Lake Huron, forming the international border between Michigan's Upper Peninsula and Ontario, Canada. This isn't a typical inland lake — it's a massive, current-driven river system that funnels all of Lake Superior's outflow through the famous Soo Locks at Sault Ste. Marie. The river ranges from narrow shipping channels to wide bays and island-studded stretches, with depths varying from shallow rocky flats to deep navigation channels dredged for freighter traffic.
Fishing is genuinely world-class here. The St. Marys is one of the few places in Michigan where you can catch Atlantic salmon — a holdover from stocking programs in the rapids below the locks. Lake trout ("lakers") are abundant, and walleye, northern pike, yellow perch, and whitefish round out the fishery. The river's strong current and cold Lake Superior water create unique conditions you won't find on any inland lake. With seven launches in Chippewa County alone, access is solid. Beyond fishing, the river is famous for freighter watching — massive Great Lakes ore carriers and ocean-going vessels pass through the shipping channel daily, and the Aune Osborn Campground right on the riverbank is a favorite spot to watch them slide by. Ice fishing is popular in winter on the calmer bays and backwaters, though the main channel's current can make ice unpredictable.