Angwin is a census-designated place (CDP) in Napa County, California, best known as the site of Pacific Union College. 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.

Napa County is a county north of San Pablo Bay located in the northern portion of the U.S. state of California. As of the 2020 census, the population was 138,019. The county seat is the City of Napa. Napa County was one of the original counties of California, created in 1850 at the time of statehood. Parts of the county's territory were given to Lake County in 1861.