A Natural History of the Sonoran DesertThe Sonoran Desert is one of the most wildly diverse and fascinating regions in the world. Covering southeastern California, the southern half of Arizona, most of Baja California, and much of the state of Sonora, Mexico, this vast area is home to an amazing variety of plants and animals. Its terrain varies dramatically, from parched desert lowlands to semiarid tropical forests and frigid subalpine meadows. A Natural History of the Sonoran Desert