Port Costa was founded in 1879 as a landing for the railroad ferry Solano, owned and operated by the Central Pacific Railroad. This put Port Costa on the main route of the transcontinental railroad. The Solano, later joined by the Contra Costa, carried entire trains across the Carquinez Strait from Benicia to Port Costa, from whence they continued on to the Oakland Pier. For a time, it was also the United States' busiest wheat-shipping port and had a reputation as a colorful, sometimes violent community.After California's wheat output dropped in the early 20th Century and especially, after the Southern Pacific (which took over the operations of the Central Pacific) constructed a railroad bridge at Martinez in 1930 to replace the ferry crossing, Port Costa lost population and importance. Bill Rich was an influential property owner and raconteur. Since the late 1960s, it has mainly been a small shopping venue for antique hunters and a gathering place for bikers and motorcyclists.Port Costa's first post office was established in 1881.