Westminster is a city in western Orange County, California, United States. Westminster was founded in 1870 by Rev. Lemuel Webber as a Pres…Westminster is a city in western Orange County, California, United States. Westminster was founded in 1870 by Rev. Lemuel Webber as a Presbyterian temperance colony and was incorporated in 1957. Westminster is bordered by the city of Seal Beach on the west, by Garden Grove on the north and east, and by Huntington Beach and Fountain Valley on the south. Santa Ana, the county seat of Orange County, is east of Westminster.