Sonoita Creek is a tributary stream of the Santa Cruz River in Santa Cruz County, Arizona. It originates near and takes its name from the abandoned Pima mission in the high valley near Sonoita. It flows steadily for the first of its westward course past Patagonia, its bird sanctuary and Patagonia Lake, but sinks beneath the sand before joining the Santa Cruz River a few miles north of Nogales. This confluence provides water for Tumacácori and Tubac and collects in the marsh lands around San Xavier del Bac downstream, to the north. The Santa Rita Mountains lie to the north and the Canelo Hills, Red Mountain and the Patagonia Mountains lie to the south. Harshaw Creek is a southern tributary which joins the Sonoita near Patagonia. Harshaw Creek drains the area between the Patagonia Mountains to the west and the high San Rafael Valley grasslands to the east. The ghost town of Harshaw lies within its watershed.