The red willow is a small tree up to 45 ft (14 m) in height. Like most other willows, it commonly grows along riverbanks and in other areas with high soil moisture.
The red willow occurs along the coast of Baja California and in California north to Cape Mendocino. It occurs east of the San Joaquin Valley in the lower elevation western foothills of the Sierra Nevada; it is absent from the Central Valley itself. Small occurrences can be found in Oregon, Nevada, and New Mexico. In Arizona it is found in the central transition zone of the Mogollon Rim and in the central Grand Canyon. Its distribution extends to the Virgin River canyon of southwestern Utah.
The Kutenai called red willow mukwuʔk, and used it in basketry.