Day is an unincorporated community in Modoc County, California. It is located 22 miles west of Adin, at an elevation of 3645 feet. A post office operated at Day from 1888 to 1925 and from 1926 to 1953. The lightining-sparked Day Fire in 2014 started just north of the community, ultimately destroying 6 structures and injuring 7 people.