Guadalupe Canyon Creek, tributary to the San Bernardino River joins it at just below Dieciocho de Augusto, Sonora.
Whitewater Draw: originally considered the upper reach of the Rio de Agua Prieta, it enters Mexico as the head of Rio de Agua Prieta, which runs southward then southeast to join the Rio de San Bernardino, at La Junta de los Rios, Sonora, about 24.5 miles southeast of Douglas, Arizona.