Anderson Lake is a deep lake in the Squamish-Lillooet region of southwestern British Columbia. On the northwest side are the Bendor Range and Cadwallader Range. On the southeast is the Cayoosh Range. By road, the southern end is about northeast of Pemberton. Name origin In 1827, Francis Ermatinger of the Hudson's Bay Company (HBC), the first European explorer, referred to the Seton and Anderson lakes as the first and second Peseline Lake (various spellings). In 1846, Alexander Caulfield Anderson ventured along the lakes when seeking a new HBC fur brigade route from Fort Alexandria. In 1858, Governor James Douglas commissioned Anderson to establish a route to the goldfields during the Fraser Canyon Gold Rush. Encouraged by the governor, he named the first lake after himself. Dimensions and tributaries The lake is long and averages wide. The surface area is . The mean depth is and maximum depth is . The size and depth help trap glacial silt entering from tributaries which would cloud the water. The lake has not completely frozen in recent centuries but has in the past. The water is a few degrees warmer than Seton Lake. At the north end, the outflow is the Seton River. Anticlockwise, the main tributaries are Sundquist Creek, Six Mile Creek, Connel Creek, Xusum Creek, McGillivray Creek, Mellott Creek, Scutt Creek, D'Arcy Creek, Gates River, Pinney Creek, McDonnell Creek, Wade Creek, and Lost Valley Creek. The rapid Gates River at the south end (formerly called Anderson Creek) is the primary inflow. Geology and topography The region comprises a mix of volcanic and sedimentary rocks. At the end of the Last Glacial Period (LGP), Seton and Anderson were a single continuous lake, with a level about higher than present. At the Seton Portage area, erosion and landslides of weak rocks susceptible to rapid weathering tumbled into the lake, and tributaries deposited sediment. Over tens of thousands of years, the accumulation created separate lakes, and a river formed from Anderson to Seton, which by 1910 was about lower (currently ). Minimal agricultural land exists along the mountainous shores of the lake beyond a limited area at the portage. Here, a noticeable gap in the mountains indicates a large landslide on the east side. Climate During 1964–2016, the mean annual winter temperature was and summer was . The area falls within the rain-shadow of the Coast Mountains, experiencing a semi-arid low mean annual precipitation of