Paralleling Interstate 710 south-southwest, the river then crosses under former California State Route 42 and the interstate as it receives the Rio Hondo from the left, from the mouth. The Rio Hondo ("deep river") now serves as a distributary for the San Gabriel River to the east via the Whittier Narrows Reservoir. The river then crosses under I-105 and shifts slightly southwest, then flows east of Compton and west of Bellflower. After crossing under California State Route 91, it receives Compton Creek from the right, from the mouth. After crossing under Interstate 405 for the second time, from the mouth, it draws close to the Dominguez Channel to the west and flows due south to its outlet in Long Beach, under Interstate 710, past the RMS "Queen Mary", and into the Port of Long Beach.