Cottonwood is a census-designated place in Shasta County, California, United States. Its population is 6,268 as of the 2020 census, up from 3,316 from the 2010 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 in either direction. It is 4 miles south of Anderson.