The 113-kilometre (70 mi) long Great Bear River, which drains the Great Bear Lake westward through marshes into the Mackenzie River, forms an important transportation link during its four ice-free months. It originates at south-west bay of the lake. The river has irregular meander pattern 350-metre (1,150 ft) wide channel with average depth 6 metres (20 ft). Historic air photos show no evidence of bank erosion or channel migration in a 50-year period. The settlement of Tulita is located at the mouth of the river.