Green Lake is the largest and most northerly lake in the Resort Municipality of Whistler, British Columbia, Canada. It is the source of the Green River, a tributary of the Lillooet River, and is fed by the River of Golden Dreams, which issues from Alta Lake, which is at the height of land dividing the Green River drainage from that of the Cheakamus River t…Green Lake is the largest and most northerly lake in the Resort Municipality of Whistler, British Columbia, Canada. It is the source of the Green River, a tributary of the Lillooet River, and is fed by the River of Golden Dreams, which issues from Alta Lake, which is at the height of land dividing the Green River drainage from that of the Cheakamus River to the south, which is a tributary of the Squamish River. Also feeding Green Lake are Fitzsimmons Creek, which originates in the valley above Whistler Village between Blackcomb and Whistler Mountains, and Rainbow Creek, which descends from Rainbow Mountain via the Alpine Meadows subdivision. A former minor ski hill, Rainbow, is located midway between Alpine Meadows and Emerald Estates near the lake's western extremity.