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. Angwin is a Cornish surname (see Cornish surnames) meaning "the white" (an = the; gwynn = white) and is comparable to the English surname "White."
Angwin is home to a large number of Seventh-day Adventists. In 1909, Pacific Union College, an Adventist liberal arts college, moved from Healdsburg to Angwin.