The Thompson River is a major tributary of the Fraser River in the south-central portion of British Columbia, Canada. The Thompson River has two main branches called the South Thompson and the North Thompson. The river is named for Columbia River explorer David Thompson. The North Thompson originates in the mountains west of the community of Valemount and flows generally south towards Kamloops and the confluence with the South Thompson. The North Thompson valley provides the primary connection from the southern parts of the province with the Yellowhead Pass, the lowest pass through the Rocky Mountains. The major tributary is the Clearwater River which joins the North Thompson at Clearwater.