The Yukon River is a major watercourse of northwestern North America. From its source in British Columbia, Canada, it flows through the Canadian territory of Yukon, which is itself named after the river. The lower section of the river continues westwards through the US state of Alaska to the mouth of the river at the Bering Sea.

The river is 1980 miles (3,190 kilometres) long and empties into the Bering Sea at the Yukon–Kuskokwim Delta ecoregion. The drainage area is over 320,000 square miles, of which 125,000 square miles lies within Canada, a total drainage area larger than the size of the entire state of Texas.

The Yukon River is the largest river system in Alaska, and the fifth largest river drainage in North America. Some Yukon River Chinook salmon migrate over 2,000 river miles to spawn in Canadian spawning grounds in the Yukon Territory. Yukon River Chinook salmon eggs will incubate for one year and, after hatching, these young salmon will rear in freshwater for about a year before migrating to the ocean.

After leaving the freshwater as smolts, these fish spend their first summer in the near shore waters of Norton Sound and the Northern Bering Shelf (north of Nunivak Island). Prior to their first winter at sea, Yukon River Chinook salmon migrate south and further offshore in the Bering Sea where they spend the next 2 - 5 years before their return back to the Yukon River as adults to spawn.