Upper Summit Lake (British Columbia) River, Great Slave Lake and the Mackenzie River into the Beaufort Sea portion of the Arctic Ocean. Upper Summit Lake (British Columbia) Upper Summit Lake is a lake in Regional District of Fraser-Fort George, in the Central Interior of British Columbia, Canada, about north of the city of Prince George and south of the community of Bear Lake. It lies just west of Highway 97 (John Hart Highway). Upper Summit Lake is about long and wide, and lies at an elevation of . There are no inflows, and an unnamed creek flows from the southern tip of the lake to
Mackenzie River is scant, despite the efforts of many researchers. Many archaeological sites have probably been destroyed by flooding, freeze-thaw and erosion. The Inuvialuit, Gwich'in and other indigenous peoples have lived along the river for thousands of years; however, the oldest evidence of continuous occupation stretches back only about 1300–1400 years, at the Gwich'in community of Tsiigehtchic. The Mackenzie provided the major route into Canada's northern interior for European explorers as early as the late 18th century. Scottish explorer Alexander Mackenzie travelled the river in the hope it would lead to the Pacific Ocean, but instead reached its mouth on the Arctic