State Route 242 is an approximately 3.4-mile (5.5 km) state highway in Contra Costa County, California that links Interstate 680 at the Pleasant Hill–Concord border to State Route 4 in Concord. Along with Interstate 580, State Route 24, Interstate 680 and State Route 4, it serves as the most direct route between the San Francisco Bay Area and the Sacramento–San Joaquin River Delta region.