California State Route 123

State Route 123
San Pablo Avenue
SR 123 highlighted in red
Route information
Maintained by Caltrans
Length	7.375 mi[1] (11.869 km)
Major junctions
South end	I-580 in Oakland
Major intersections	SR 13 in Berkeley
North end	I-80 in Richmond
Location
Country	United States
State	California
Counties	Alameda, Contra Costa
Highway system
State highways in California Interstate US State Scenic History Pre‑1964 Unconstructed Deleted Freeways
← SR 121 → SR 124

State Route 123 (SR 123) is a 7.39-mile (11.89 km) state highway in the U.S. state of California in the San Francisco Bay Area. Named San Pablo Avenue for almost its entire length except for its northernmost 0.10 miles (0.16 km), SR 123 is a major north–south state highway along the flats of the urban East Bay. Route 123 runs between Interstate 580 in Oakland in the south and Interstate 80 at Cutting Boulevard in Richmond in the north. San Pablo Avenue itself, a portion of Historic US 40, continues well past the SR 123 designation south to Downtown Oakland and north to Crockett.