From the plaque:
Built in 1900 of Arizona
red sandstone, this is the oldest existing county courthouse
in Southern California. Significant and far-reaching court
decisions were handed down here, including the 'Whipstock'
case dealing with slant oil drilling, interpretation of
farm labor law, and the Overell trial which resulted in
law regulating explosives.
Plaque placed by the State Department of Parks and Recreation in cooperation with the Orange County Board of Supervisors and Let's Improve Santa Ana (L.I.S.A.). March 11, 1970