The Swift River is a river that begins in Yukon Territory and flows southwest into British Columbia to its mouth at the east side of Teslin Lake on the Teslin River system. The river drains the uppermost portion of the Cassiar Mountains and in its lower reaches traverses the Nisutlin Plateau, which lies along the east side of Teslin Lake north of the mouth of the Jennings River, which is to the south of the Swift.