inland waterway between the Canadian capital of Ottawa and Lake Ontario at Kingston, Ont. Completed in 1832, the 200-km (125-mile) canal uses both the Rideau and Cataraqui rivers and a series of lakes, including Upper Rideau Lake at its summit, to create its waterway. Built as a military project to provide a secure connection between Montreal and Kingston, the canal has been widely used for recreational purposes for the past century. One of the oldest continuously operated canals in North America, with 24 hand-operated lock stations, the Rideau system was listed as a Canadian Heritage River in 2000. The canal was designated a UNESCO World Heritage site in 2007.
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