The Las Guijas Mountains are a small northwest - southeast trending mountain range in southern Pima County, Arizona. The range is approximately long by . Surrounding ranges includes the Cerro Colorado Mountains to the northeast, the Tumacacori Mountains of Santa Cruz County to the east, the San Luis Mountains to the south and the Baboquivari Mountains across the Altar Valley to the west. Arivaca is immediately to the southeast and the old mining townsite of Las Guijas is in the wash just north of the range.