stream in central Yukon Territory, Canada, one of the main headstreams of the Yukon River. It was named in 1840 by Robert Campbell for Sir John Henry Pelly, governor of the Hudson's Bay Company. Rising in the Mackenzie Mountains near the southeastern boundary of the territory, the river flows westward, receiving its two major tributaries, Ross and Macmillan rivers, before joining the upper course of the Yukon at Fort Selkirk. The Pelly, 378 miles (608 km) in length, is navigable for small boats for more than 200 miles (320 km), to Hoole Canyon, except in the shallows of Bradens Canyon.