Gananoque River - Course and Watershed

Course and Watershed

The Gananoque River begins at Gananoque Lake in incorporated Leeds and the Thousand Islands township. It flows south, passes through the community of Marble Rock, then turns southwest and reaches the community of Maple Grove. It heads again south, takes in the right tributary Mud Creek, passes under Ontario Highway 401, and enters the town of Gananoque. It then flows over the concrete dam for the Gananoque Generating Station, in service since 1939, and empties into the Saint Lawrence River where that river is part of the Thousand Islands region.

At one time, the Gananoque's watershed extended north to the Rideau River watershed, but, in 1830, the flow of water was diverted near the town of Newboro, Ontario to enter the Cataraqui River watershed as part of the construction of the Rideau Canal. Up until that time, the river had been an important water transportation corridor.