The route begins at SR 113 in Knights Landing in Yolo County.

It then heads northward and enters Colusa County, where it has a short overlap with SR 20.

It then continues northward to its end at SR 32 in Hamilton City.

[4] Except where prefixed with a letter, postmiles were measured on the road as it was in 1964, based on the alignment that existed at the time, and do not necessarily reflect current mileage.

[5] Segments that remain unconstructed or have been relinquished to local control may be omitted.