Route 72 officially begins at State Route 19 in Pico Rivera, but the portion between State Route 19 and Interstate 605 is not maintained by Caltrans. Caltrans maintenance of the highway begins at the junction of I-605 in Whittier. The route follows Whittier Boulevard for its entire length, heading southeast through Whittier as a four-lane arterial street. SR 72 crosses with Los Angeles County Route N8 at Colima Road and ends at the intersection of SR-39 (Beach Boulevard) in La Habra. Whittier Boulevard is a major commercial corridor in Whittier, though it does not go through the city center, which is north of the highway.