Cottonwood is a census-designated place (CDP) in Shasta County, California, United States. The population was 3,316 at the 2010 census, up from 2,960 at the 2000 census. Cottonwood was a stagecoach town where a settlement was established in 1849. The first Post Office was opened in 1852. Cottonwood is equidistant between Redding and Red Bluff, 15 miles (24 km) in both directions.