SR 145 travels through the center of the San Joaquin Valley, remaining a rural two-lane road in its entirety.

After passing through the town of Helm, SR 145 heads northeast as McMullin Grade, before turning north again as South Madera Avenue.

[2] Various crops such as cotton, table grapes, tomatoes and melons are grown along the route in one of the most productive agricultural areas in the world[citation needed].

[5] 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.

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