Yuma County, Arizona
Arizona's sunniest county with over 300 sunny days per year, a global agricultural powerhouse producing 90% of North America's winter lettuce, and home to one of America's oldest river crossings along the Colorado River.
Yuma County, one of Arizona's original four counties established on November 8, 1864, occupies the southwestern corner of Arizona at the confluence of the Colorado and Gila Rivers. Named after the Quechan people — sometimes called the Yuma — who have inhabited this strategic river crossing for centuries, the county covers 5,522 square miles of Sonoran Desert, river bottomlands, and remote wilderness areas. Yuma, the county seat, is one of Arizona's oldest European settlements and holds the Guinness World Record for the sunniest city on Earth, with an average of 4,055 hours of sunshine annually — over 90% of possible daylight hours.
The county's history is shaped by its position at a critical crossing of the Colorado River. Long before the arrival of Europeans, the Quechan controlled this crossing and traded with peoples across the Southwest. Spanish missionaries and explorers crossed here in the 1700s, American surveyors and emigrants in the 1800s, and the completion of the railroad transformed Yuma into an important junction city. Today, Yuma County is a major military presence — Marine Corps Air Station Yuma and Yuma Proving Ground (the Army's largest military installation by area) together dominate much of the county's land — alongside its extraordinary agricultural production. Winter brings a massive influx of "snowbirds," retirees and tourists escaping cold northern winters to enjoy Yuma's legendary sunshine and warmth.
County Information
Demographics & Economy
Photos
Major Attractions
Yuma Territorial Prison State Historic Park
The Yuma Territorial Prison, operated from 1876 to 1909, was the most notorious prison in the American Southwest during the territorial era. Built by its own inmates using granite blocks quarried from nearby hillsides, the prison held 3,069 prisoners during its 33-year operation — including 29 women. Despite its fearsome reputation as a hellhole, the prison had a library, a hospital, and even an early electrical generator. Today, the Yuma Territorial Prison State Historic Park preserves the surviving structures including the main cell block and guard tower, with a museum featuring exhibits on the colorful history of the prison and its inhabitants.
Location: Yuma, overlooking the Colorado River
Features: Original cell blocks, museum exhibits, guard tower, prison cemetery, overlook of the Colorado River
Yuma Crossing National Heritage Area
Yuma's strategic position at the only natural ford of the lower Colorado River made it one of the most important crossings in the American West. The Yuma Crossing National Heritage Area preserves the historic sites along the riverfront that tell this story, including the Quartermaster Depot (which supplied Army posts throughout the Southwest), Ocean-to-Ocean Bridge (the first automobile bridge across the lower Colorado), and the Colorado River State Historic Park. The heritage area offers interpretive sites, walking trails, and excellent river access along the revitalized waterfront district.
Location: Downtown Yuma along the Colorado River
Features: Historic quartermaster depot, interpretive exhibits, riverfront walking trails, Gateway Park, Colorado River State Historic Park
Imperial Sand Dunes Recreation Area
The Imperial Sand Dunes — known locally as the Algodones Dunes — stretch along the California-Arizona border near Yuma and represent one of the largest dune systems in North America, covering approximately 40 miles in length and up to 6 miles wide. The dunes rise to heights of 300 feet in some areas. While the Imperial Sand Dunes are technically in California's Imperial County, they are intimately linked to the Yuma area and are easily accessed from Yuma. The dunes are popular for off-road vehicle recreation, sandboarding, and photography. The area appears in numerous films, including the Tatooine sequences in Star Wars.
Location: West of Yuma along the California border
Features: Massive sand dunes reaching 300 feet, OHV recreation, sandboarding, photography, camping at Glamis and other areas
Kofa National Wildlife Refuge
Covering nearly 665,400 acres of remote wilderness in northeastern Yuma County, the Kofa National Wildlife Refuge is one of the largest and most remote wildlife refuges in the contiguous United States. The refuge protects the rugged Kofa Mountains, New Water Mountains, and Castle Dome Mountains, along with their distinctive flora and fauna. The refuge harbors one of the largest wild desert bighorn sheep populations in Arizona, along with Gambel's quail, cactus wrens, golden eagles, and numerous other species. The refuge is also home to Arizona's only native population of Washington fan palms, found in a remote side canyon reachable by a one-mile hike.
Location: Northeastern Yuma County
Features: Desert bighorn sheep viewing, remote wilderness hiking, native palm canyon, wildlife photography, primitive camping
Mittry Lake Wildlife Area
Mittry Lake, formed by a backwater of the Colorado River north of Yuma, is one of the most productive wildlife areas in the Sonoran Desert. The lake and its surrounding marshes, cottonwood-willow forests, and upland desert support an exceptional diversity of birds — over 285 species have been recorded here — along with mule deer, coyotes, beavers, and numerous other mammals. The wildlife area offers fishing (largemouth bass, catfish, crappie), non-motorized boating, birdwatching, and primitive camping along the shores. The contrast between the lush riparian zone and the surrounding stark desert is dramatic and beautiful.
Location: North of Yuma along the Colorado River
Features: Fishing, non-motorized boating, birding, wildlife viewing, primitive camping, riparian ecosystem access
Frequently Asked Questions
Yuma County is one of the most productive agricultural regions in the world, with its importance rooted in several key factors:
- Winter lettuce capital: The Yuma agricultural district produces approximately 90% of all fresh leafy vegetables consumed in North America during winter months (November through March). This includes lettuce, spinach, kale, broccoli, and other cool-season crops.
- Climate advantage: While most of North America experiences winter, Yuma's mild temperatures (daytime highs of 65-75°F) and over 300 sunny days per year create ideal winter growing conditions.
- Colorado River water: Water from the Colorado River, delivered through an extensive network of canals and the Wellton-Mohawk Irrigation and Drainage District, makes agriculture possible in this otherwise hyper-arid desert.
- Economic scale: Yuma's agricultural industry generates over $3 billion annually and supports tens of thousands of jobs in farming, packing, transportation, and related industries.
- Global reach: Yuma-grown produce is shipped to supermarkets throughout North America, and the region is a major producer of medjool dates, citrus, and specialty crops as well.
- The Yuma area is also one of the nation's leading producers of Sudan grass, small grains, alfalfa, and cotton.
Yuma's exceptional winter climate — warm, sunny, and dry — makes it one of the most popular destinations for "snowbirds," the informal term for retirees and winter visitors who leave cold northern states and Canada to spend the winter in a warm climate:
- Yuma County's winter population more than doubles during the peak season (November through March), with an estimated 90,000 or more snowbird visitors arriving annually.
- RV parks are a major element of the Yuma snowbird economy — the Yuma area has one of the highest concentrations of RV parks and campgrounds in the United States. The sprawling public lands around Quartzsite (in La Paz County, but drawing from the Yuma region) host hundreds of thousands of winter RVers.
- Snowbirds typically rent spaces at RV parks, park on federal BLM land, or stay in rental properties for months at a time.
- The economic impact of the winter visitor population is enormous, supporting restaurants, retail, medical services, entertainment, and other businesses through the winter months.
- Many snowbirds return to the same location year after year and develop deep community connections with both other snowbirds and year-round residents.
Yuma County has one of the largest military footprints of any county in the United States:
- Marine Corps Air Station Yuma (MCAS Yuma): One of the world's busiest military airfields, MCAS Yuma hosts the 3rd Marine Aircraft Wing and numerous tenant commands. The station is the host of the annual Yuma Air Show, one of the largest free air shows in the country. The combination of year-round good weather, large airspace, and nearby bombing ranges makes it ideal for aviation training.
- Yuma Proving Ground (YPG): Operated by the U.S. Army, YPG is the largest military installation by area in the United States, covering 1,300 square miles of desert. The facility tests virtually every conventional weapon system used by the Army, taking advantage of the extreme climate conditions and isolation. YPG is the Army's primary artillery, aerial delivery, and munitions testing center.
- Together, these two installations are major employers in Yuma County, with thousands of active-duty military, civilian employees, and contractors.
- The military's large land holdings mean that much of Yuma County's terrain is off-limits to civilians, contributing to the county's relatively low population density despite its proximity to the California border.
Yuma County has a distinct visitor season driven by its extreme summer heat:
- Winter (November-March): This is by far the best and most popular time to visit. Daytime temperatures range from the comfortable mid-60s to mid-70s°F, with little chance of rain. This is when snowbirds arrive in force, agricultural fields are green and active, and outdoor activities are pleasant. Mornings can be cool, with temperatures in the 40s-50s°F.
- Spring (April-May): Temperatures begin rising, reaching the 80s-90s°F. Still comfortable for outdoor activities, especially in the morning and evening. Crowds are smaller than winter. Wildflowers may bloom in the desert surrounding Yuma.
- Summer (June-September): Yuma experiences some of the hottest temperatures of any city in the United States, routinely exceeding 110°F and occasionally reaching 115°F or higher. Outdoor activities are extremely hazardous during daytime. Most snowbirds have left. Monsoon moisture occasionally brings brief thunderstorms. Summer visitors should restrict outdoor activities to early morning and late evening only.
- Fall (October): Temperatures begin to moderate, dropping back into the 80s-90s°F. An excellent shoulder season before the winter crowds arrive.
Major Communities
Yuma
County seat and Arizona's sixth-largest city, population ~96,000, sunniest city on Earth
San Luis
Population ~36,000, major border city adjacent to San Luis Rio Colorado, Mexico
Somerton
Population ~16,000, agricultural community in the Yuma Valley
Wellton
Population ~3,200, small agricultural town east of Yuma along I-8
Dateland
Tiny community famous for its date shakes, surrounded by date palm groves along I-8
Fortuna Foothills
Population ~27,000, large unincorporated suburban community east of Yuma