By car
State Route 24, through the venerable Caldecott Tunnel, is the main entrance to Contra Costa from San Francisco, Oakland and Berkeley. Interstate 680 is the main route linking Contra Costa to the South Bay and Silicon Valley to the south, and to Sacramento to the north. Interstate 580 links Contra Costa to central Alameda County to the west, and to Stockton and the Central Valley to the east.
By plane
There are no major airports in Contra Costa County with regularly scheduled passenger service, though there are several general aviation airports. One must either use the Bay Area airports serving San Francisco, Oakland, or San Jose, or the Central Valley airports serving Stockton or Sacramento. The county also has two airports that are not currently providing passenger service:
Buchanan Field Airport, located in Concord
Byron Airport, located two miles 3 km south of Byron