The Mojave Desert (pronounced: /mɵˈhɑːviː/ mo-hah-vee) is a rain shadow, mostly high desert area, that occupies a significant portion of southeastern California and smaller parts of central California, southern Nevada, southwestern Utah and northwestern Arizona in the United States. The Mojave Desert's boundaries are generally defined by the presence of Yucca brevifolia (Joshua trees), considered an indicator species for this desert. It is the driest of the North American deserts.