Black Donald Lake is a reservoir lake in the Township of Greater Madawaska, Renfrew County and the Township of North Frontenac, Frontenac County in Eastern Ontario, Canada. It is on the Madawaska River and is part of the Saint Lawrence River drainage basin.The major inflow, at the west, is the Madawaska River, which arrives directly from Centennial Lake at the same elevation as Black Donald Lake. Secondary inflows are Black Donald Creek and Little Black Donald Creek at the centre north. The major outflow is also the Madawaska River, which flows over the dam at the Ontario Power Generation Mountain Chute Generating Station (hydroelectric) to Norcan Lake at the southeast. The Madawaska River then flows via the Ottawa River to the Saint Lawrence River and thence to the Atlantic Ocean.The settlement of Black Donald is on the southeast shore of the lake. From the outflow of the lake almost to the major inflow of the Madawaska River from Centennial Lake, Black Donald Lake forms the boundary between Greater Madawaska, Renfrew County and North Frontenac, Frontenac County.
