The expansive Grass Valley covers nearly three-fourths of this Wilderness and ranks as its primary topographical feature. The area lies fairly flat, with a series of scattered hills, yellow to reddish brown in color, with elevations from 200 feet to 600 feet above the desert floor to the west. You'll find a few Joshua trees, but the vegetation is dominated by (you guessed it) a creosote bush scrub community. Raptors forage here, and desert tortoises and Mojave ground squirrels find suitable habitat in this barren area, which is devoid of both water and trails. The non-Wilderness corridor of an old road divides the Wilderness into eastern and western halves, and the China Lake Naval Weapons Center shares the eastern border.