Opinicon

Lake Opinicon lies among wooded lakes and rivers inland from the eastern end of Lake Ontario. Before the canal age, two Indigenous canoe routes from the St Lawrence converged at the lake and continued towards the Ottawa River. The surrounding waters also formed hunting and fishing grounds. At the outlet, William Davis established a sawmill around 1818–1820.

The Rideau Canal transformed this older route into a navigable connection between the Ottawa River and Lake Ontario. Engineers built a lock and dam at Davis's mill, raising the water level of Opinicon Lake. The work formed part of a chain of locks, dams and channels linking rivers and lakes across the watershed. Overseen by Lieutenant-Colonel John By, the canal opened in 1832, providing a route away from the exposed St Lawrence frontier.