Yukon River, one of the largest rivers in North America. From headwaters in northern British Columbia the river flows 1,875 miles (3,018 km) in a giant curve through the Yukon Territory and Alaska to the Bering Sea. The river's most northerly point is just above the Arctic Circle, near Fort Yukon, Alaska. With its many tributaries, the Yukon drains a basin of 330,000 square miles (855,000 km 2 )—the fifth largest in North America. Principal tributaries in Canada include the Teslin, Pelly, White, and Stewart rivers; in Alaska, the Porcupine, Tanana, and Koyukuk rivers. Most of the Yukon basin is mountainous or hilly. Large tracts along the river in Alaska are low-lying and marshy.
Although navigable to Whitehorse (in the Yukon Territory) and beyond, the river is little used for transportation. It is icebound from early October to mid-May. The riverboats that once formed a chief means of transit have been replaced by airplanes, railways, and roads.