Saint Marys Falls is the old name for the St. Marys Rapids, the stretch of the St. Marys River at Sault Ste. Marie, Michigan, where Lake Superior's outflow drops toward Lake Huron. Locks and hydroelectric dams now carry most of that water around the rapids, and the flow over them is set by gates rather than by the river.
The falls
The rapids drop over 20 feet in 0.8 mile, and the difference in level the Soo Locks overcome is 21 feet. Locks and three hydroelectric stations have greatly reduced their volume. Building those works diverted over 90% of Lake Superior's outflow and left over 62 acres of the rapids dry. Today the three hydro plants take most of the river, and the Compensating Works, a line of gates across the head of the rapids, must always pass at least a half-gate equivalent into the main channel. In September 2026 the rapids flow was cut from about 17,800 to 16,400 cubic feet per second, roughly three fully open gates, out of a total river flow of 82,600.
Getting there
The documented walking route is on the Canadian side, from the Sault Ste. Marie Canal National Historic Site at 1 Canal Drive, Sault Ste. Marie, Ontario. Visitors cross the lock gates, on an accessible path, to the 2.2 km Attikamek Trail on South St. Marys Island, or over a bridge to Whitefish Island, toward the rapids. No public approach from the Michigan bank is documented.
When to go
Flow over the rapids follows monthly gate settings more than the season. Salmon runs occur at the rapids from July (Atlantic) through December (coho). The canal's visitor centre is open weekdays 10 a.m. to 5 p.m. until October 9 in 2026, and the lock closes for the season on October 16.
On site
Fishing is banned in the canal and its approach and in the channel between South St. Marys and Whitefish islands, a spawning sanctuary. Whitefish Island belongs to Batchewana First Nation.
History and name
Indigenous people lived at Bawating, "the place of the rapids," for more than 2,000 years, harvesting whitefish from birchbark canoes. French arrivals named the settlements Sault Ste. Marie. The first lock on the Michigan side opened in 1855, and the Canadian canal followed in 1895.
Nearby
Lower Tahquamenon Falls is about 40.6 miles away, and Upper Tahquamenon Falls about 42.8 miles. In town, Soo Locks Park on the Michigan side, open late March through mid-January, is where visitors watch freighters pass through the locks.
Distances are straight-line.