The route formerly continued west under a railroad bridge near Pio Pico State Historic Park and then over the San Gabriel River as it entered Pico Rivera and met State Route 19 at Rosemead Boulevard. After about a mile and a half, the route crossed a narrow steel bridge over the Rio Hondo into Montebello. There, it continued towards Atlantic Boulevard. From there, it continued further to its end at Downey Road. Whittier Boulevard itself continues past Downey Road towards downtown Los Angeles. These segments have been relinquished back to the cities of Pico Rivera and Montebello, and are not included in the length of SR 72.