The Miramichi River is a roughly 250-kilometre river system draining east-central New Brunswick into Miramichi Bay on the Gulf of St. Lawrence. It consists of two main branches — the Southwest Miramichi and the Northwest Miramichi — along with numerous tributaries. The river has long been central to the region's logging and fishing industries, and its waters are considered among the cleanest in the world. Atlantic salmon are the river's most celebrated inhabitants, and the Miramichi basin historically supported one of the largest salmon populations in North America. Nearly every bend and rapid along the Southwest Miramichi carries a distinctive name reflecting centuries of use by Indigenous peoples, lumbermen, and sport anglers.

The Southwest Miramichi is the largest and longest branch of the system. One well-documented route runs approximately 70 kilometres from Half Moon Pit on Highway 107 near Deersdale to Boiestown, where the Taxis River joins the Southwest Miramichi — a trip typically completed over three days with no portages, suited to intermediate paddlers comfortable with moving water. A shorter section runs 11.3 kilometres from Priceville to Doaktown, with an elevation change of 18 metres, rated easy with moderate current and typically completed in two to three hours. The McNamee/Priceville Footbridge, the longest suspension footbridge in New Brunswick at 200 metres, serves as a notable landmark and common put-in for this section. Water levels can be monitored using the Environment Canada hydrometric gauge at Blackville (station 01BO001); a reading of around 1.5 metres generally means most rocks are covered and the river flows well.

The river is wide and gravelly through much of its length. Islands split the current into shallower, narrower channels, and choosing the wrong channel in low water may require wading. Late spring through early summer offers the best water levels, though the river typically carries enough volume to remain runnable through most of the paddling season. Unseasonably warm and dry conditions can reduce water levels significantly, making some sections very shallow by late summer or early fall.

Established campsites are plentiful along the river on multi-day routes, though firewood at popular sites tends to be picked clean, making it advisable to bring your own. Canoe, kayak, and tube rentals along with shuttle services are available from outfitters including Storeytown Cottages near Doaktown and Wilson's Sporting Camps. At the City of Miramichi, where the branches converge, the river becomes tidal, and paddlers should plan trips with tidal patterns in mind.