Many famous people are associated with these Contra Costa County historic places including John Marsh, Alice Tisdale Hobart, Paul DeMartini, Joel Clayton and Roswell Butler Hard.
Some of the country's most noteable architects helped create the Contra Costa County places including Albert Kahn, Thomas Boyd, R.B. Hard, Cumming and Weymouth, William Wilde, Dragovitch & Cavagnaro and Continental Fireproof Co.. Prominent architectural styles found in Contra Costa Country are Classical Revival, Gothic Revival and Italian Villa.