The Yukon River is a major watercourse of northwestern North America. The river's source is in British Columbia, Canada, from which it flows through the Canadian Yukon Territory (itself named after the river). The lower half of the river lies in the U.S. state of Alaska. The river is 3,190 kilometres (1,980 mi) long and empties into the Bering Sea at the Yukon–Kuskokwim Delta. The average flow is 6,430 m³/s (227,000 ft³/s). The total drainage area is 832,700 km² (321,500 mi²), of which 323,800 km² (126,300 mi²) is in Canada. The total area is more than 25% larger than Texas or Alberta.
The longest river in Alaska and Yukon, it was one of the principal means of transportation during the 1896–1903 Klondike Gold Rush. A portion of the river in Yukon—"The Thirty Mile" section, from Lake Laberge to the Teslin River—is a national heritage river and a unit of Klondike Gold Rush International Historical Park. Paddle-wheel riverboats continued to ply the river until the 1950s, when the Klondike Highway was completed. After the purchase of Alaska by the United States in 1867, the Alaska Commercial Company acquired the assets of the Russian-American Company and constructed several posts at various locations on the Yukon River.
The Yukon River has had a history of pollution from military installations, dumps, wastewater, and other sources. However, the Environmental Protection Agency does not list the Yukon River among its impaired watersheds, and water quality data from the U.S. Geological Survey shows relatively good levels of turbidity, metals, and dissolved oxygen. The Yukon and Mackenzie rivers have much higher suspended sediment concentrations than the great Siberian Arctic rivers.The Yukon River Inter-Tribal Watershed Council, a cooperative effort of 70 First Nations and tribes in Alaska and Canada, has the goal of making the river and its tributaries safe to drink from again by supplementing and scrutinizing government data.