A 67-year-old man and his 43-year-old son were the only two people on board.
A ground team located the plane early Monday morning in Solano County north of Benicia, Civil Air Patrol officials said.
The Beechcraft BE-36 airplane took off from Buchanan Field Airport in Concord Saturday afternoon on its way to Arcata-Eureka Airport in McKinleyville, but had not landed by Saturday night.
The CAP was activated Saturday night to search for the aircraft.
ABC7 News contributed to this story.