Desert National Wildlife Refuge

Desert National Wildlife Refuge is the largest wildlife refuge in the lower 48: 1.6 million acres established in 1936 to protect the Mojave's biggest intact desert bighorn sheep habitat, with its front door at Corn Creek just 30 miles north of the Strip up US-95. Entry, parking and even camping are completely free. Corn Creek itself is an oasis of spring-fed ponds, a boardwalk, short desert trails toward the Sheep Range foothills, and a visitor center with exhibits, staffed Thursday through Monday, 8 AM to 4 PM, while the grounds stay open daily from sunrise to sunset.

Understand its two halves. The Corn Creek area takes any car - four paved miles off the highway - and rewards 1–2 easy hours. The 150-plus miles of backcountry roads beyond (Mormon Well, Alamo Road) demand high clearance and preferably 4WD, and the refuge's entire western half overlaps the Air Force's test range and is closed to the public. There's no food, gas or reliable cell coverage anywhere, summer offers extreme heat and no shade, and the bighorn that the whole place exists to protect show themselves on their own schedule, best at dawn in the cooler months. Free primitive camping (six sites at Desert Pass, plus dispersed turnouts) makes it the closest true wilderness night to Las Vegas.