Lillooet Lake is a lake in British Columbia, Canada about 25 km in length and about 33.5 square kilometres (22 mi²) in area. It is about 95 km downstream from the source of the Lillooet River, which resumes its course after leaving Little Lillooet Lake, aka Tenas Lake (tenass in the Chinook Jargon means little). Immediately adjacent to the mouth of the upper Lillooet River is the mouth of the Birkenhead River and just upstream along the Lillooet is the confluence of the Green River, which begins at Green Lake in the resort area of Whistler.