There are two Chapman Avenues in Orange County, named for two different people. Phil Brigandi says, "they both have off-ramps off the 57 freeway, which causes no end of confusion!"
Brigandi wrote the book "Orange County Place Names A-Z." He says Chapman in Orange was named for an L.A. lawyer.
"But then up in Fullerton, there's a Chapman Avenue, named for C.C. Chapman, for Charles Chapman, one of the famous early Valencia orange growers here."
He was so successful, he became known as the "Orange King of California." Chapman made his big money in real estate and became even wealthier when he struck oil in 1919. His wells in Placentia pumped over 5,000 barrels a day. The "Orange King" became Fullerton's first mayor and the principal benefactor of the college that bears his name: Chapman University. Charles Chapman's autobiography was called "The Career of a Creative Californian."