The Rivière des Prairies, known in English as the Back River, is a delta channel of the Ottawa River in southwestern Quebec. It originates at the Lake of Two Mountains, flows west to east through the Hochelaga Archipelago, passing on either side of Île Bizard before forming the boundary between the Island of Montreal to the south and Île Jésus (Laval) to the north. It ultimately empties into the St. Lawrence River at the eastern tip of the Island of Montreal. The Kanien'kehá:ka people called it Skowanoti, meaning "River behind the island," reflecting its geographic position relative to the islands it surrounds.

The river is a freshwater body and draws considerable interest from anglers, with species including channel catfish, common carp, freshwater drum, lake sturgeon, northern pike, rock bass, smallmouth bass, and walleye present in its waters. Paddlers sharing the river with fishing activity should be aware of this recreational use, particularly during warmer months when fishing pressure is likely highest. Fishing regulations include size and daily limits for walleye, lake sturgeon, and bass, with specific open seasons for each species.

The river runs through a heavily urbanized corridor between two major Canadian cities, Montreal and Laval, giving it a distinctly urban character. Several bridges cross the river along its length, including the Louis Bisson Bridge, and the island of Île aux Chats is a notable geographic feature visible along the route. The urban setting means paddlers will encounter infrastructure and development along the shoreline rather than a remote or wilderness experience.

The Paddling.com listing places the river under the Laval region, confirming it as a recognized paddling location, though detailed information on specific access points, put-in and take-out locations, and paddling-specific amenities is limited. Paddlers planning a trip should research current access conditions locally before launching.