Teslin Lake is a large lake spanning the border between British Columbia and Yukon, Canada. It is one of a group of large lakes in the region of far northwestern BC, east of the upper Alaska Panhandle, which are the southern extremity of the basin of the Yukon River, and which are known in Yukon as "the Southern Lakes" (the other major ones in the group are Atlin Lake and Tagish Lake but include Bennett and Lindeman Lakes, the headwaters of the Yukon River itself). The lake is fed and drained primarily by the Teslin River, south and north, but is also fed from the east by the Jennings River and the Swift River, and from the west by the Hayes River.