The Rideau Canal, also known unofficially as the Rideau Waterway, connects Canada's capital city of Ottawa, Ontario, to Lake Ontario and the Saint Lawrence River at Kingston, Ontario. It is 202 kilometres in length. The name Rideau, French for "curtain", is derived from the curtain-like appearance of the Rideau River's twin waterfalls where they join the Ottawa River. The canal system uses sections of two rivers, the Rideau and the Cataraqui, as well as several lakes.
In winter, a section of the Rideau Canal passing through central Ottawa becomes officially the world's largest and second longest skating rink.
The cleared length is 7.8 kilometres (4.8 mi) and has the equivalent surface area of 90 Olympic ice hockey rinks. It runs from the Hartwell locks at Carleton University to the locks between the Parliament Buildings and the Château Laurier, including Dow's Lake in between. It serves as a popular tourist attraction and recreational area and is also the focus of the Winterlude festival in Ottawa.
The Skateway is open 24 hours a day. The length of the season depends on the weather, but typically the Rideau Canal Skateway opens in January and closes in March.
In 1971–1972, the Skateway's second winter, the skating season was 90 days long, which is the longest season so far. 2015–2016 was the shortest Rideau Canal Skateway season, being a mere 34 days long (and with only 18 skating days).
According to en.wikipedia