Rivière L'Assomption is one of the most significant rivers in the Lanaudière region of Quebec, stretching over 120 miles in length. It originates at Lac L'Assomption near Mont-Tremblant and flows southward, eventually emptying into the St. Lawrence River near the town of Repentigny. The river passes through a mix of rural and urban landscapes, transitioning from the Canadian Shield in its upper reaches — characterized by waterfalls, rapids, and exposed bedrock — to a slower, more meandering lower section as it approaches the St. Lawrence.

The upper portions of the river, particularly around Saint-Côme, offer whitewater paddling with Class 2–3 rapids and are well-suited to paddlers looking to develop technical skills. Instruction through the Quebec Federation is available on various sections, allowing paddlers to progress through different skill levels. The water in the Saint-Côme area is notably clear and translucent. The lower river takes on a different character, with a slow current and winding course that suits relaxed flatwater paddling.

A well-established 12 km canoe circuit operates out of the city of L'Assomption, departing from Parc Léo-Jacques (257, boulevard Barret), with a shuttle service transporting paddlers to the put-in at the Saint-Gérard-Majella sector. Canoe, single and double kayak, and paddleboard rentals are available through this circuit. A separate 6 km guided descent is offered by Au Canot Volant in the Saint-Côme area, catering to families, beginners, and those seeking a shorter outing.

Water quality varies along the river's length. Swimming is considered acceptable in the urban stretch near Parc Léo-Jacques, but water quality downstream near Repentigny does not meet swimming standards. Anglers frequent the river for channel catfish, smallmouth bass, walleye, yellow perch, lake sturgeon, and mooneye.

A speed restriction of 25 km/h applies to motorized vessels on a section of the river between coordinates 46°01′73°27′ and 46°03′73°28′, which is relevant for paddlers sharing the water with powerboats. The river is recognized as a classic paddling destination in Quebec, with canoe-tripping routes documented by Canot Kayak Québec and Eau Vive Québec.