California State Route 33 begins in Ventura as a short freeway (Ojai Freeway). SR 33 then continues north as Maricopa Highway, an undivided surface road, through Ojai, following Matilija Canyon past the easternmost extremity of the Santa Ynez Mountains in Los Padres National Forest, and passing over the Transverse Ranges at Pine Mountain Summit. As SR 33 comes down into the Cuyama Valley, it comes up to a junction with SR 166 east of Cuyama. Route 33 continues with Route 166 as they enter Kern County for about to Maricopa where the routes separate. In Maricopa, Route 33 turns northwest, following the western side of the San Joaquin Valley. Between Taft and Avenal it roughly parallels Interstate 5 and the eastern foothills of the Temblor and Diablo ranges; for the first of the portion following the axis of the Midway-Sunset Oil Field. Northwest of Avenal, it turns due west to enter Coalinga, then turns northeast and soon becomes concurrent with I-5 for . Thereafter, it departs due north near Cantua Creek, turns northwest at Mendota, through Firebaugh and meets State Route 152 in Dos Palos, in which it runs concurrently due west for approximately ten miles. It departs again west of Los Banos, turning north to Santa Nella (where it has an interchange with I-5), and roughly parallels I-5 and the San Joaquin River until its northern terminus at I-5 and Bird Road southeast of Tracy.