Highway 70 is a state highway that runs between Highway 99 in Catlett and Hallelujah Junction in Lassen County. In the Yuba-Sutter area, it is also called "Oroville Highway," because it is often used for traveling to Oroville in Butte County. From south to north in the Yuba-Sutter area, it passes through Catlett, East Nicolaus, Rio Oso, Plumas Lake, Arboga, Olivehurst, Alicia, West Linda, South Yuba, Linda, and Marysville.
Highway 70 overlaps with part of "El Centro Boulevard" south of Rio Oso. From south to north in Marysville, it overlaps with E Street, 9th Street, and B Street. On 9th Street and part of B Street in Marysville, it also overlaps with Highway 20.