Avon, Contra Costa County, California
Avon, formerly known as Associated and Marsh, is an unincorporated community in Contra Costa County, California, United States. It is located on the Southern Pacific Railroad east-northeast of Martinez, at an elevation of 10 feet.
A post office operated at Avon from 1912 to 1960. It was originally called Marsh, and in 1913 the name was changed to Associated. The name Marsh was in honor of John Marsh. The name Associated was for the Tidewater Associated Oil Company, owner of the site.
