Upper Rideau Lake is a freshwater lake located in the municipality of Rideau Lakes, United Counties of Leeds and Grenville in Eastern Ontario, Canada. A part of the Saint Lawrence River drainage basin, the lake has the highest altitude of any body of water within the Rideau Canal system.
The Rideau River (French: Rivière Rideau, Ojibwe: Pasapkedjinawong) is a river in Eastern Ontario, Canada. The river flows north from Upper Rideau Lake and empties into the Ottawa River at the Rideau Falls in Ottawa, Ontario. Its length is 146 kilometres (91 mi).
As explained in a writing by Samuel de Champlain in 1613, the river was given the name "Rideau" (French for 'curtain') because of the appearance of the Rideau Falls. The Anishinàbemowin name for the river is Pasapkedjinawong, 'the river that passes between the rocks'.