Riviere des Prairies

Rivière des Prairies
Aerial view looking east, of Rivière des Prairies with Louis Bisson Bridge in the foreground. The island "Ile aux Chats" can be seen near the center.
Country	Canada
Province	Quebec
Region	Montreal and Laval
Basin features
Main source	Lake of Two Mountains
River mouth	Saint Lawrence River

The Rivière des Prairies (literally River of the Prairies, sometimes called the The Back River in English) is a delta channel of the Ottawa River in southwestern Quebec, Canada. The indigenous inhabitants of what's now known as the Island of Montreal called it Skowanoti, meaning "River behind the island".

Flowing west to east, the Rivière des Prairies bisects the Hochelaga Archipelago and originates in the Lake of Two Mountains. It flows on either side of Île Bizard (part of Montreal), it then divides the Island of Montreal (Montreal) to the south from Île Jésus (Laval) to the north, after which it flows into the St. Lawrence River at the eastern tip of the Island of Montreal.

The river contains a large number of islands, including Île Bizard, the Îles Laval (Île Bigras, Île Pariseau, Île Verte and Île Ronde) belonging to Laval, and Île de la Visitation, a nature park belonging to Montreal. There are also islands named Île Mercier, Île Ménard, Île Jasmin, Île Barwick, Île de Roxboro, Île aux Chats, Île Paton, Île Perry, Île Lapierre, Île Boutin, Île Rochon and Île Gagné.

The Rivière des Prairies has many rapids. Rapids are shown in several places on the 1879 map of Henry Whitmersome Hopkins, and on Gordon and Gotch's map of the Island of Montreal from 1924. Named rapids of the river, starting from the west are the "Rapides de Cap-Saint-Jacques", the Lalemant(Dutchman) Rapids that are located between Île Bizard and Laval (with a ferry), the "Rapides du Cheval Blanc"(Whitehorse rapids) that are located in between the borough of Pierrefonds-Roxboro and Sainte-Dorothée, the Laval rapids, the "Sault-au-Récollet Rapids" that are located north of Bordeaux Prison, and ending with the "Rapides de la Rivière des Prairies".