<Tr> <Td_colspan="2"> Map of the Mackenzie River watershed </Td> </Tr> <P> The Mackenzie River (Slavey language: Deh - Cho (tèh tʃhò), big river or Inuvialuktun: Kuukpak (kuːkpɑk), great river) is the largest and longest river system in Canada, and is exceeded only by the Mississippi River system in North America . It flows through a vast, isolated region of forest and tundra entirely within the country's Northwest Territories, although its many tributaries reach into four other Canadian provinces and territories . The river's mainstem runs 1,738 kilometres (1,080 mi) in a northerly direction to the Arctic Ocean, draining a vast area nearly the size of Indonesia . It is the largest river flowing into the Arctic from North America, and with its tributaries is one of the longest rivers in the world . </P> <P> Rising out of the marshy western end of Great Slave Lake, the Mackenzie River flows generally west - northwest for about 300 km (190 mi), passing the hamlet of Fort Providence . At Fort Simpson it is joined by the Liard River, its largest tributary, then swings towards the Arctic, paralleling the Franklin Mountains as it receives the North Nahanni River . The Keele River enters from the left about 100 km (62 mi) above Tulita, where the Great Bear River joins the Mackenzie . Just before crossing the Arctic Circle, the river passes Norman Wells, then continues northwest to merge with the Arctic Red and Peel rivers . It finally empties into the Beaufort Sea, part of the Arctic Ocean, through the vast Mackenzie Delta . </P> <P> Most of the Mackenzie River is a broad, slow - moving waterway; its elevation drops just 156 metres (512 ft) from source to mouth . It is a braided river for much of its length, characterized by numerous sandbars and side channels . The river ranges from 2 to 5 km (1.2 to 3.1 mi) wide and 8 to 9 m (26 to 30 ft) deep in most parts, and is thus easily navigable except when it freezes over in the winter . However, there are several spots where the river narrows to less than half a kilometre (0.3 mi) and flows quickly, such as at the Sans Sault Rapids at the confluence of the Mountain River and "The Ramparts", a 40 m (130 ft) deep canyon south of Fort Good Hope . </P>

Where does the mackenzie river start and end