Rideau

Rideau is a toponym in Ontario, Canada, most often associated with a chain of waterways and places around Ottawa. The best-known use is the Rideau Canal, a historic waterway that links Ottawa to Kingston on Lake Ontario. Built in the 1820s to defend against invasion by the United States, it comprises a series of locks along a 202-kilometre route and is a UNESCO World Heritage Site and a National Historic Site of Canada. In winter, sections of the canal are closed to navigation and host the Rideau Canal Skateway, claimed to be the world's longest skating rink.

The Rideau River is a tributary of the Ottawa River that runs through eastern Ontario, including Ottawa, and forms part of the canal's water system. The Rideau River valley is known for parks and green spaces within the city.

Rideau Hall is the official residence of the Governor General of Canada, located in Ottawa, and serves as a venue for official functions and state ceremonies.

Rideau Street is a major commercial thoroughfare in downtown Ottawa, running near the central business district and intersecting with major transit routes.

The name Rideau also appears in other Ontario locales and lakes known as the Rideau Lakes system, which lies upstream of the canal near Kingston.

The word Rideau itself is of French origin, meaning curtain or drapery, and was used in early French exploration to name geographic features such as the Rideau Falls and the river leading to the canal.