Yuma County is a county in Arizona, United States, in the state’s southwestern corner along the lower Colorado River. It had a population of 203,881 at the 2020 census and covers 5,519 square miles (14,290 km2), centred near 32°47′N 113°58′W.
Yuma is the county seat, and its postal code is 85364. The county has three cities — Yuma, San Luis and Somerton — plus the town of Wellton and more than a dozen unincorporated communities and census-designated places. Yuma County runs on Mountain Standard Time year-round (it does not observe daylight saving) and carries FIPS code 04027.
Towns & Villages in Yuma County
Most of the county’s population lives along the Interstate 8 corridor between the California line and Gila Bend, with the rest scattered across desert farmland irrigated from the Colorado River.
| Place | Type | Pop. | ZIP |
|---|---|---|---|
| Yuma | City · seat | — | 85364 |
| San Luis | City | — | 85349 |
| Somerton | City | — | 85350 |
| Wellton | Town | — | 85356 |
| Fortuna Foothills | CDP | — | 85367 |
| Gadsden | CDP | — | 85336 |
| Dateland | CDP | — | 85333 |
| Tacna | CDP | — | 85352 |
| Wellton Hills | CDP | — | 85356 |
| Martinez Lake | CDP | — | 85365 |
| Yuma Proving Ground | CDP | — | 85365 |
| Roll | Unincorp. | — | 85347 |
| Hyder | Unincorp. | — | — |
| Mohawk | Unincorp. | — | — |
| Kofa | Unincorp. | — | — |
ZIP Codes
- 85364 — Yuma (also serves the eastern edge of Fortuna Foothills)
- 85365 — Yuma (also serves Martinez Lake and Yuma Proving Ground)
- 85367 — Fortuna Foothills
- 85349 — San Luis
- 85350 — Somerton
- 85356 — Wellton and Wellton Hills
- 85333 — Dateland
- 85352 — Tacna
- 85336 — Gadsden
- 85347 — Roll
Hyder, Mohawk and Kofa are too small to carry their own post office and rely on the nearest listed ZIP.
Geography
Yuma County sits at the bottom of Arizona’s southwest corner, where the Colorado and Gila rivers meet. The terrain is low Sonoran Desert — irrigated farmland along the river bottoms giving way to open desert, dune fields and the Gila and Kofa mountain ranges further east. Elevations range from under 100 feet near the Colorado River to over 4,800 feet in the Kofa Mountains.
The county borders La Paz County to the north, Maricopa County to the northeast, Pima County to the east, Imperial County, California, across the Colorado River to the west, and the Mexican municipalities of San Luis Río Colorado (Sonora) to the south and Mexicali (Baja California) to the southwest.
Demographics
Yuma County had 203,881 residents at the 2020 census, with more recent estimates putting the population near 224,000. Yuma city and Fortuna Foothills are the two largest communities in the county. The county’s median household income runs well below the Arizona figure of $77,315, reflecting its heavily agricultural, seasonal-labor economy. Population density is roughly 37 people per square mile, concentrated almost entirely along the river corridor and Interstate 8.
Economy & Local Life
Agriculture anchors the county: Yuma County grows nearly all of Arizona’s dates and supplies most of the leafy vegetables eaten in the United States between November and March, earning Yuma the nickname “Winter Lettuce Capital of the World.” The military is the other major employer, with Marine Corps Air Station Yuma and the U.S. Army’s Yuma Proving Ground both based in the county. Yuma Regional Medical Center and the Yuma Union High School District round out the largest employers. The Yuma Jaycees Silver Spur Rodeo runs every February, and the city marks New Year’s Eve with its Lettuce Drop from the downtown water tower.
History
Yuma County was organized on November 9, 1864, as one of Arizona Territory’s four original counties, and takes its name from the Yuma (Quechan) people who have lived along the lower Colorado River for centuries. The county seat was first La Paz before moving in 1871 to Arizona City, renamed Yuma in 1873. The city of Yuma itself incorporated as a town in 1902 and as a city in 1914. The Colorado River crossing near Yuma was a key point on the Butterfield Overland Mail route and later the Southern Pacific Railroad, making the county a historic gateway between California and the rest of the Southwest.
Getting There
Interstate 8 runs the length of the county, linking San Diego to the west with Casa Grande and Interstate 10 to the east; U.S. Route 95 runs north-south through Yuma toward Quartzsite and south toward San Luis and the Mexican border. Historic U.S. Route 80 and Arizona State Route 195 provide secondary access.
- San Luis — 25 miles south of Yuma
- Somerton — 13 miles south of Yuma
- Wellton — 30 miles east of Yuma
- Dateland — 55 miles east of Yuma
Yuma International Airport offers commercial flights, and Amtrak’s Sunset Limited stops at Yuma Station on its Los Angeles–New Orleans route.
Frequently Asked Questions
What is the Yuma postcode?
Yuma’s main ZIP codes are 85364 and 85365.
What county seat serves Yuma County?
Yuma is the county seat.
How big is Yuma County?
It covers 5,519 square miles (14,290 km2), most of it open Sonoran Desert.
What was Yuma County’s population at the 2020 census?
203,881, making it one of Arizona’s larger counties by population.
What crops does Yuma County grow?
Leafy vegetables, melons, dates and other winter produce grown along the Colorado River irrigation district.
Which military bases are in Yuma County?
Marine Corps Air Station Yuma and the U.S. Army’s Yuma Proving Ground.
What counties border Yuma County?
La Paz County to the north, Maricopa and Pima counties to the east, plus Imperial County, California, and the Mexican states of Sonora and Baja California across the border to the south and west.
More counties in this state: Towns and villages in Arizona.