Cheakamus River, Mountain brook in Squamish-Lillooet Regional District, Canada

The Cheakamus River is a river in the Squamish-Lillooet Regional District of British Columbia, Canada, originating at McBride Glacier and flowing through Garibaldi Provincial Park before joining the Squamish River. Along its course, it passes through forests, lakes, and open valley sections.

The Cheakamus River drains a 1,070 km² basin and is 75 km long. In 1957 the Daisy Lake Dam was built, and an 11 km tunnel now diverts water to a 158 MW powerhouse on the Squamish River. On August 5, 2005, a Canadian National train derailed north of Squamish; a tank car of sodium hydroxide fell into the river and killed about 500,000 fish of 10 species, with coho, rainbow trout, steelhead, cutthroat trout and lampreys hardest hit.

The river's name comes from Chiyakmesh, a word from the Squamish language that reflects the long relationship between the local indigenous people and this waterway. Along certain stretches, visitors can notice traces of that connection in place names and interpretive signs posted near the banks.

The river is easy to reach via British Columbia Highway 99, with parking available along Cheakamus Lake Road and nearby pullouts. Trails and water access are generally more manageable during the drier summer months.

The river's name comes from Chiyakmesh, meaning "people of the fish weir", a village of the Squamish people and a Squamish Nation reserve. The 2005 derailment spilled sodium hydroxide into the water and killed an estimated 500,000 fish of ten species; king salmon, rainbow trout, steelhead, cutthroat trout and lampreys were hardest hit, while chum salmon were spared by their migration habits.