With its raw, wild beauty and epic landscapes, the vast Chihuahuan—whose borders reach into New Mexico, Arizona, Texas, and Mexico—is the hemisphere's most biologically varied desert. But as Joe Kane discovers, it is also a microcosm of America itself: diverse, expansive, mutable, and welcoming to all who visit

Last March, I landed in Tucson in weather that felt like no weather at all, rented a car, and set course south and east for the Chihuahuan Desert, the biggest, wildest desert in the Western Hemisphere. I think of the Chihuahuan as the Next Desert, the one you head for when you've had it with Phoenix and Las Vegas and Palm Springs and you're looking for the real thing.

For a long time, like a lot of people, I'd had no idea there was a Chihuahuan Desert ("You mean like the dog?" friends asked invariably). Yet it covers more than twenty percent of Mexico and vast tracts of Arizona, New Mexico, and Texas—all told, some 250,000 square miles, an area five times the size of New York State. On this trip, my destination was the Northern Chihuahuan, the quadrant north of the Mexican border, which contains not only true desert but also wetlands, rivers, lakes, and forests. At its heart are the Sky Islands, a dramatic archipelago of more than forty truncated mountain ranges that rise spectacularly from North America's largest remaining grasslands. With its vast plains and snowcapped peaks, the Northern Chihuahuan is the classic open range of the American West. It looks like the setting for every cowboy movie ever made.

The Northern Chihuahuan is cattle country, but its wide-open landscapes have an epic, outlaw quality. It was here that Geronimo's family was slaughtered, and that he and his Apache followers later exacted their revenge. It's where Pancho Villa rose, rode, and was murdered. It's the cauldron in which young men in Cormac McCarthy's novels burn through their innocence. Today, drug smugglers and illegal immigrants—men, women, and children—die by the dozens every month trying to claw their way through its Old Testament torments.

Yet the land is also surprisingly accessible, endowed not only with national parks, monuments, and wildlife areas but also, increasingly, with comfortable lodges and spas, first-class restaurants, and professional guides willing to unlock the mysteries of the hemisphere's most biologically diverse desert. But what first drew me to the Northern Chihuahuan was its combination of mountains and high prairie, which create biological "edges" that support a tremendous amount of wildlife, including mountain lions, ocelots, black bears, kit foxes, coyotes, jaguars, and other large carnivores. These edges also provide critical food and flyways for raptors and millions of migratory birds, including such imperiled species as the ferruginous hawk and the mountain plover. Aldo Leopold, the father of the modern conservation movement, called the Northern Chihuahuan "the cream of creation."

For this trip, I decided to visit three distinct zones in the Northern Chihuahuan: the Sky Islands and high prairie along the Arizona–New Mexico border; the chiseled cliffs and canyons of the Rio Grande and Big Bend National Park in southwestern Texas; and the Gila River Basin in south-central New Mexico, where the desert climbs to meet the dense forests of the Rocky Mountains.