On the Canadian side of St Mary's River, follow the 2.2km Attikamek walking trail around South St Mary's Island to see this canal dating to 1895, once the world's longest lock and the first to operate with electrical power. It was also novel in using an emergency swing dam to protect the lock in case of accident. The majority of freighter traffic occurs further afield in the American locks; the older Canadian lock is used for recreational vessels only.

The meandering path winds through wooded knolls, encircles the trenchlike lock and dips under the International Bridge, allowing visitors to grasp the interesting juxtaposition of nature and industry.