The Counties That Are Almost Entirely Desert
Desert counties are not always seas of sand. In the United States, major desert systems include the Mojave, Sonoran, Chihuahuan, and Great Basin. The last of these is a cold desert, where winter snow and freezing temperatures are common. County boundaries often cut across mountain ranges, irrigated valleys, river corridors, and towns, so almost no county is desert in every acre. The places below stand out because most of their land falls within recognized desert ecoregions.
San Bernardino County, California
San Bernardino County has the strongest numerical case on this list. Its official Community Indicators program places 77% of the county in the North Desert Region and 17% in the East Desert Region. That leaves only a small share outside those two planning regions. The county covers more than 20,000 square miles, larger than several states.
Mojave National Preserve fills a vast section of the interior with dunes, volcanic terrain, Joshua trees, and dry mountain ranges. Kelso Dunes rise more than 600 feet above the surrounding desert floor. Farther south, Joshua Tree National Park reaches into the county around Twentynine Palms. The Colorado River supports a greener strip near Needles.
Higher ground looks different. The San Bernardino Mountains hold pine forest, ski areas, and communities around Big Bear Lake. Those elevations occupy a much smaller footprint than the immense desert basins stretching across the county's north and east.
Imperial County, California
Nearly all of Imperial County lies within the Colorado Desert, the California section of the Sonoran Desert. The area ranks among the driest parts of the state, and annual rainfall in parts of the county can stay below three inches. Low basins, sparse scrub, exposed sediment, and dune fields cover much of the land away from farms and towns. The Imperial Valley looks unusually green because Colorado River water reaches it through a vast irrigation system. That agriculture occupies desert terrain rather than a naturally humid valley. The Algodones Dunes run for roughly 40 miles near the Arizona border and form one of the largest dune systems in North America. Tall ridges of shifting sand fall within nearby recreation areas. West of the valley, eroded badlands and dry mountain slopes lead toward Anza-Borrego country. The Salton Sea occupies the county's northern edge, filling a low basin below sea level.
Yuma County, Arizona
Yuma County sits inside the Sonoran Desert, within the particularly dry Yuma Desert subdivision on EPA ecoregion maps. The county has some of the lowest elevations and hottest summer temperatures in Arizona. Rainfall near Yuma averages only a few inches a year.
Colorado River water changes the appearance of the southwestern corner dramatically. Irrigated fields around Yuma produce winter vegetables, citrus, and other crops on land that would otherwise support desert vegetation. Outside that narrow agricultural zone, creosote bush, bursage, palo verde, and cactus spread across broad plains and rocky slopes.
Kofa National Wildlife Refuge covers more than 660,000 acres farther east. Its sharp mountain ranges rise abruptly above open Sonoran basins and provide habitat for desert bighorn sheep. The refuge also protects palm canyons, washes, and large stretches of undeveloped desert. The Gila Mountains and surrounding federal land add more rugged terrain near the county's southern half.
La Paz County, Arizona
Western Arizona's La Paz County sits mainly within the Sonoran Basin and Range ecoregion shown on EPA maps. Desert valleys occupy most of the county, broken by dry mountain chains and washes that may remain empty for long periods. The Colorado River forms the western boundary and creates the main concentration of permanent surface water. Parker developed beside that river, while Quartzsite grew in the much drier interior.
Quartzsite is surrounded by huge tracts of Bureau of Land Management property. Low mountains, alluvial fans, old mining ground, and open scrub extend in every direction. Farther north, vegetation begins to show greater Mojave influence as elevation and winter temperatures change. Along the Colorado, cottonwoods, wetlands, irrigated land, and recreation areas form a narrow green corridor. A few miles inland, the scenery returns to exposed rock, palo verde, creosote, and dry washes.
Clark County, Nevada
Clark County's conservation planning data provide unusually detailed land-cover figures. Mojave desert scrub accounts for 65.5% of the county. Blackbrush covers another 20%, while salt desert scrub adds about 4%. Pinyon-juniper woodland occupies only a small fraction by comparison. Mixed conifer and alpine habitats are smaller still. Las Vegas fills the largest urbanized section, but much of the surrounding county remains open desert. At Valley of Fire State Park, red Aztec sandstone stands exposed above creosote-covered basins. Lake Mead National Recreation Area adds broad desert valleys, volcanic formations, and the Colorado River corridor. The Spring Mountains rise west of Las Vegas and reach nearly 12,000 feet at Charleston Peak. Bristlecone pine and conifer forest occur high on those slopes. Below them, desert vegetation returns quickly as elevation drops toward the Las Vegas Valley and Pahrump-facing basins.
Nye County, Nevada
Nye County stretches across a huge section of south-central Nevada and spans two major desert systems. The southern end approaches the Mojave, while most of the county lies within the Central Basin and Range. EPA describes that ecoregion through dry basins, shrublands, playas, and parallel mountain ranges.
Around Beatty and the Amargosa Valley, creosote and other Mojave plants become common. Death Valley National Park reaches across the California line into a small part of the county. Farther north, sagebrush and saltbush dominate colder basins. Tonopah sits above 6,000 feet and experiences winter snow despite its arid setting.
Long valleys such as Big Smoky and Railroad Valley separate narrow mountain chains across the county. Springs and higher slopes support pockets of wetter vegetation. The valley floors remain much drier, with large distances between settlements and little permanent surface water.
Lincoln County, Nevada
Lincoln County runs through classic Basin and Range country north of Las Vegas. EPA maps place much of it within the Central Basin and Range, with Mojave influence increasing toward the south. Sagebrush, greasewood, blackbrush, and salt-tolerant shrubs occupy many of the broad valleys. Pinyon and juniper appear higher on the surrounding slopes. Cathedral Gorge State Park holds one of the county's most unusual landforms, where erosion has carved soft bentonite clay into narrow passages, fluted walls, and sharp ridges near Panaca. Kershaw-Ryan State Park is a striking local contrast, a sheltered canyon where springs support cottonwoods and other vegetation. South of Caliente, Rainbow Canyon cuts through volcanic rock and exposes bands of red and tan stone. The towns are small and widely spaced, leaving large portions of the county undeveloped. Dry basins continue for miles between each mountain range.
Esmeralda County, Nevada
Esmeralda County lies near the transition between the Great Basin and Mojave deserts. Bureau of Land Management records for the Montezuma Peak area note valley precipitation near three inches annually. Higher mountain ground can receive several times that amount. The difference is visible in the vegetation. Greasewood, rabbitbrush, saltbush, and sparse grasses dominate lower elevations, while pinyon-juniper appears on cooler slopes.
Fish Lake Valley spreads beneath the White Mountains along the western side of the county. Elsewhere, playas and pale alkali flats occupy closed basins with no outlet to the sea.
Goldfield sits near the center of this terrain, surrounded by old mining sites and open desert. The county has fewer than 1,000 residents across more than 3,500 square miles. Development is sparse enough that natural basin-and-range patterns remain easy to see across most road journeys.
Luna County, New Mexico
Luna County sits in the northern Chihuahuan Desert, and desert landscape is its predominant physical feature in state environmental records. Average annual precipitation is around 10 inches near Deming. Spring winds frequently lift dust from exposed soil and dry agricultural ground, a problem serious enough to appear in state air-quality planning. The Florida Mountains rise southeast of Deming and reach more than 7,000 feet. Their rocky slopes overlook broad basins covered with yucca, mesquite, grasses, and desert shrubs. Rockhound State Park sits on the western side of the range, within close view of that terrain. North of town, the Cooke's Range rises as another high ridge above the desert floor. The Tres Hermanas Mountains mark the southern part of the county near the Mexican border. Between those ranges, the land stays open, dry, and thinly settled, with agriculture concentrated where groundwater makes cultivation possible.
El Paso County, Texas
The far western tip of Texas belongs to the Chihuahuan Desert, and EPA ecoregion maps place El Paso County inside that system. Urban development covers much of the central valley, yet desert terrain remains extensive around the metropolitan area.
The Franklin Mountains cut directly through El Paso and rise to more than 7,000 feet. Franklin Mountains State Park protects thousands of acres of rocky slopes where lechuguilla, sotol, yucca, ocotillo, and other Chihuahuan plants grow close to the city. East of the range, wide desert flats continue toward Hudspeth County.
The Rio Grande forms the county's main river corridor and supports irrigated land along parts of the valley. Away from it, natural surface water is scarce. The city's average annual rainfall is under 10 inches, with much of it arriving during summer thunderstorms. Dry mountain foothills remain visible from neighborhoods throughout the metropolitan area.
Hudspeth County, Texas
Hudspeth County covers more than 4,500 square miles east of El Paso, almost entirely within the arid Trans-Pecos. EPA maps place its basins and mountains within Chihuahuan Desert ecoregions. The county has only a few thousand residents, so settlement occupies a tiny part of its land area. Long desert valleys separate the Quitman, Diablo, Eagle, and Finlay ranges. Yucca, creosote, lechuguilla, grasses, and thorny shrubs cover much of the lower ground. Near the northern boundary, salt flats spread south of the Guadalupe Mountains across an enclosed basin where evaporation leaves pale mineral deposits. Interstate 10 crosses the southern part of the county, but large areas farther north contain little development. Surface streams are rare and often intermittent. Water collects briefly in washes after thunderstorms before disappearing into dry soils and basin sediments.
Culberson County, Texas
Culberson County contains one of the sharpest elevation changes in the Chihuahuan Desert. Guadalupe Peak reaches 8,751 feet inside Guadalupe Mountains National Park, the highest point in Texas. The surrounding basins sit thousands of feet lower and receive far less moisture. EPA ecoregion mapping places most of the county within Chihuahuan Desert units.
Salt Basin lies west of the Guadalupe Mountains and contains broad flats formed in a closed drainage system. Sparse desert vegetation surrounds the pale basin floor. Van Horn occupies another open valley farther south, where mountain ranges remain visible across long distances.
Higher elevations in the Guadalupes support pine, fir, oak, and other woodland communities. The climb from desert scrub to cooler forest happens over a relatively short horizontal distance. That vertical sequence lies within Guadalupe Mountains National Park, along with canyons, fossil reef geology, and extensive Chihuahuan lowlands around the mountain base.
Presidio County, Texas
Presidio County spreads across more than 3,800 square miles of the Trans-Pecos along the Mexican border. EPA maps show most of the county inside Chihuahuan Desert ecoregions, including desert basins, grasslands, bajadas, and mountain areas. The Rio Grande traces the southwestern boundary through deeply cut country.
Big Bend Ranch State Park protects more than 300,000 acres across Presidio and neighboring Brewster County. Volcanic formations, arroyos, desert mountains, and river canyons dominate the park's western side. Highway 170 follows the Rio Grande through some of the steepest roadside terrain in Texas.
Marfa lies on higher ground in the northern part of the county, where desert grassland becomes more prominent. South toward Presidio, elevations fall and temperatures rise. The vegetation shifts toward more typical Chihuahuan scrub, with ocotillo, yucca, mesquite, and creosote increasingly common.
Brewster County, Texas
Brewster County holds one of the clearest desert records in Texas, thanks to Big Bend National Park. The National Park Service places the park in the northern Chihuahuan Desert and puts about 98% of its area in desert. The park alone covers more than 800,000 acres, all within Brewster County.
Low elevations near the Rio Grande receive very little rain. Creosote, ocotillo, lechuguilla, and cactus cover large areas around Rio Grande Village, Castolon, and the Ross Maxwell Scenic Drive. Santa Elena Canyon cuts through limestone along the Mexican border, with walls rising sharply above the river.
The Chisos Mountains form a cooler island in the center of the park. Pine, oak, juniper, and other woodland species grow at higher elevations around the Chisos Basin. Outside the park, open ranchland and desert basins continue north toward Alpine and Marathon, where elevation moderates the heat but annual precipitation remains limited.
Tooele County, Utah
Tooele County belongs to a very different kind of American desert. The Great Salt Lake Desert covers most of the county's western side, part of the wider Great Basin, which the National Park Service classifies as a cold desert. Winter snow, freezing temperatures, and sagebrush are normal here. The Bonneville Salt Flats form the county's best-known landscape. Their white crust developed on the floor of ancient Lake Bonneville and extends for miles near Wendover. Surrounding basins contain saltbush, sagebrush, greasewood, and large playas. Long mountain ranges interrupt that flat country. The Stansbury, Onaqui, Cedar, and Deep Creek ranges reach high enough for juniper, pinyon, and other upland vegetation. Between them lie broad closed basins where water has no route to the ocean. Evaporation, low precipitation, and rain-shadow conditions shape the county far more than summer heat.
Reading The Desert In County Lines
County boundaries were drawn for administration, not ecology, yet in the driest corners of the Southwest the two nearly coincide. What separates these places is less whether they are desert than which desert and how it behaves. The Sonoran and Chihuahuan counties bake through long summers, the Great Basin and Great Salt Lake country freezes under winter snow, and the sharpest cases pair a single high range with basins that run dry for miles. Read together, they show how much of the American map is held by land where water is the scarcest thing on it.
