Angwin is a census-designated place (CDP) in Napa County, United States. California. It is part of the northern San Francisco Bay Area. The population was 3,051 at the 2010 census. Its area code is 707. Its two zip codes are 94508 and 94576. It is in the Pacific time zone. The town was named in 1874 for Edwin Angwin who ran a resort on the land the town now occupies. Edwin Angwin (1841–1919) was a native of St. Agnes, Cornwall.