Castlegar is a community in the West Kootenay region of British Columbia, Canada. In the Selkirk Mountains, at the confluence of the Kootenay and Columbia Rivers, it is a regional trade and transportation centre, with a local economy based on forestry, mining and tourism.

The Kootenays or Kootenay is a region of southeastern British Columbia. It takes its name from the Kootenay River, which in turn was named for the Kutenai First Nations people.