Chihuahuan Desert
The largest desert in North America, a high grassland-and-shrub basin straddling the Rio Grande
The Chihuahuan is the largest desert in North America, a high, mostly Mexican expanse that straddles the Rio Grande and reaches north into Texas, New Mexico, and Arizona. Estimates of its area vary with where its fuzzy edges are drawn, commonly cited between about 360,000 and 520,000 square kilometres. Lying largely above 1,000 metres on a high plateau, it is cooler and greener than its desert reputation suggests, a land of golden grasslands, shrub flats, and dramatic isolated mountain ranges.
This is a rain-shadow desert, sheltered from moisture by the Sierra Madre ranges that flank it east and west. What rain it gets falls mostly in summer, briefly greening the grasslands. The Chihuahuan harbours remarkable features: the glistening white gypsum dunes of White Sands, the spring-fed pools of Cuatro Cienegas teeming with endemic species, and an exceptional richness of cactus, agave, and yucca. It is considered one of the most biologically diverse arid regions in the world, with hundreds of species found nowhere else.
The desert has long sheltered human communities, from ancient peoples to the Apache and the farming towns strung along the Rio Grande. Spanish colonists pushed up the river valley, founding settlements that grew into the border cities of today, where El Paso and Ciudad Juarez face each other across the water. Overgrazing and groundwater pumping now press hard on its fragile grasslands, and conservation efforts span both sides of the border to protect a desert whose scale and diversity are still being mapped.