The Yukon River is not located in any U.S. state as a primary feature. The vast majority (about 1,980 miles / 3,190 km) flows through Canada's Yukon Territory and British Columbia.
Only the final ~1,000 miles (1,600 km) run through the U.S. state of Alaska before emptying into the Bering Sea.
It is the third-longest river in North America and a vital salmon habitat and transportation corridor.