State Route 37 is a state highway in the U.S. state of California that runs 21 miles (34 km) along the northern shore of San Pablo Bay. It serves as a vital connection in the North Bay region of the San Francisco Bay Area, running from U.S. Route 101 in Novato, through northeastern Marin County, and the southern tips of both Sonoma and Solano Counties to Interstate 80 in Vallejo. Sonoma Raceway and Six Flags Discovery Kingdom are accessible from Highway 37.