The Back River, formerly Backs River, is the 20th longest Canadian river and is located in the Northwest Territories and Nunavut. It rises at an unnamed lake in the North Slave Region of the Northwest Territories and flows more than 974 km (605 mi) mostly through the Kivalliq Region, Nunavut, to its mouth at the Arctic Ocean in the Kitikmeot Region of Nunavut.

The Thelon Wildlife Sanctuary, at 52,000 square kilometres (20,077 sq mi), over twice the area of Belgium, is the largest wildlife refuge in Canada. It is located in northern Canada's Arctic region, north of the tree line, straddling the Northwest Territories and Nunavut, halfway between Baker Lake and Yellowknife, and bordered on the north between the Baillie River on the west and the Consul River at the east by the Back River. It is the namesake of the Thelon River, whose river valley is resplendent with boreal forest biological diversity, hence its identification as a "Biological Site of Universal Importance" by the International Biological Program (IBP) in the 1960s.