On western-coast side of the northern portion of the ranges the California montane chaparral and woodlands sub-ecoregion of the California chaparral and woodlands ecoregion covers in southern California and northern Baja California. On western-coast side of the southern portion of the ranges the Baja California desert ecoregion covers in the southern portion of the Peninsular Ranges in Baja California and Baja California Sur. On eastern side of northern ranges, the Sonoran Desert ecoregion covers southeastern California and northeastern Baja California as far south as the town of Loreto, Baja California Sur.