Yuma County
County
Clockwise from top: Old Yuma City Hall, Ocean to Ocean Bridge, Kofa Mountains, Downtown Yuma, Yuma County administration building, McPhaul Suspension Bridge, Yuma County Courthouse and the Sonoran Desert near Yuma.
Flag Seal
Location within the U.S. state of Arizona
Arizona's location within the U.S.
Coordinates: 32°47′13″N 113°58′58″W / 32.786944444444°N 113.98277777778°W / 32.786944444444; -113.98277777778
Country	United States
State	Arizona
Founded	November 9, 1864
Named for	Yuma (Quechan) people
Seat	Yuma
Largest city	Yuma
Area
• Total	5,519 sq mi (14,290 km2)
• Land	5,514 sq mi (14,280 km2)
• Water	5.1 sq mi (13 km2)  0.1%
Population  (2020)
• Total	203,881
• Estimate  (2023)	213,221
• Density	37/sq mi (14/km2)
Time zone	UTC−7 (Mountain)
Congressional districts	7th, 9th
Website	www.yumacountyaz.gov

Yuma County is a county in the southwestern corner of the U.S. state of Arizona. As of the 2020 census, its population was 203,881.^[1] The county seat is Yuma.^[2]

Yuma County includes the Yuma, Arizona Metropolitan Statistical Area.

The county borders three states: Sonora, Mexico, to the south, and two other states to the west, across the Colorado River: California of the United States and the Mexican state of Baja California.

Being 63.8% Hispanic in 2020, Yuma is Arizona's largest majority-Hispanic county.^[3]

History

Long settled by Native Americans of indigenous cultures for thousands of years, this area was controlled by the Spanish Empire in the colonial era. In the 19th century, it was part of independent Mexico before the Mexican–American War and Gadsden Purchase.

Yuma County was one of four original Arizona counties created by the 1st Arizona Territorial Legislature.^[4] The county territory was defined as being west of longitude 113° 20' and south of the Bill Williams River.^[5] Its original boundaries remained the same until 1982, when La Paz County was created from its northern half.

The original county seat was the city of La Paz; in 1871 it was moved to Arizona City, later renamed as Yuma in 1873.^[6]

Economy

This county is the highest crop producer in the state by dollar value per year.^[7] Yuma County tops the list for the categories of vegetables + melons + potatoes + sweet potatoes at $782,293,000, and fruits + tree nuts + berries at $62,499,000.^[7] Overall this is the second (to Maricopa) producing county for all agricultural products at $1,143,068,000 per year^[7] and for organic production.^[8]: 320 Almost all of the dates (Phoenix dactylifera) in the state are grown here,^[8]: 299 about 10 million pounds (4,500 metric tons; 5,000 short tons) worth $35 million per year.^[9] This is the second highest citrus producer behind Maricopa,^[8]: 302 a distant second in grapefruit,^[8]: 302 limes,^[8]: 302 and oranges^[8]: 303 but producing far more lemons.^[8]: 302 Some olives,^[8]: 299 clingstone peaches,^[8]: 300 and plums^[8]: 301 are grown here. Yuma County produces almost all of the vegetable seed grown in the state.^[8]: 311 The average farmer age is the lowest in the state, at 56.6 years.^[8]: 326

During the winter agricultural season from November to March, some 40,000 Mexican workers cross the border daily to work in United States fields.^[10] The area is watered by the Colorado River, and the sector supplies a large part of the US leafy vegetables.^[11][12] The Yuma Lettuce Days festival and agritourism is connected to Yuma agriculture. In 2017 the county produced vegetables worth $782,293,000, ranking first in the state and third in the entire country, from 107,908 acres (43,669 ha).^[8] Fruits brought $62,499,000, also first in the state, 56th out of >3000 counties in the country.^[8] Jojoba (Simmondsia chinensis) is a valuable native crop here.^[13]: 239 From here it has also been introduced into cultivation in other countries.^[13]: 239

The Sweetpotato Whitefly (Silverleaf Whitefly, Bemisia tabaci) is a common pest here.^[14]: 47 The county is planted with large extents of several crops which serve as hosts.^[15]: 263

Date trees (Phoenix dactylifera) were planted here in the 2010s.^[16] In this county, plantations suffer from the Carob Moth (Ectomyelois ceratoniae) and the Banks Grass Mite (Oligonychus pratensis).^[16]

Leaders in the county are aware their economy is tied to that of Mexican states on the other side of the border; both have to be considered. "There are automotive plants in Ciudad Juárez, across from El Paso; aerospace plants in Mexicali, southwest of Yuma; and medical devices’ manufacturers in Tijuana, near San Diego. On the American side, there is a mix of retail stores, warehouses and trucking companies..."^[10]

Because of Yuma County's location along the U.S.-Mexico border, large numbers of aliens entering the United States illegally pass through Yuma County. From October 2004 to July 2005, some 124,400 undocumented foreign nationals were apprehended in the area, a 46% increase over the previous year.^[17] In 2014, however, only 5,902 people were apprehended. The report from the Congressional Research Service stated, "...it is unclear how much of the drop-off is due to increased enforcement and how much is a result of the U.S. economic downturn and other systemic factors".^{[18] [10]}

The Greater Yuma Economic Development Corp anticipates many agricultural jobs in the county will soon transition to robotics.^[19]

Government

The Board of Supervisors is the governing body of the county and a number of special districts. The board has members from five districts.^[20] The Board adopts ordinances, establishes programs, levies taxes, appropriates funds, appoints certain officials, and zones property and regulates development in the unincorporated area. In addition, members of the Board represent the county on numerous intergovernmental agencies.^[21]

In Arizona's first 52 years as a state, Yuma County was a primarily Democratic county, only voting for the Republican candidates four times in presidential elections prior to 1968. From 1968 onward, it has consistently voted for Republican presidential candidates. In 2016, county voters elected more Democrats to the Board than Republicans for the first time since 2004.^[22] However, their margins of victory have been reduced in recent years as the county has rapidly grown in population and become majority-Hispanic. Donald Trump only won the county by 560 votes over Hillary Clinton in the presidential election of 2016. However, Trump's margin did improve to over 4,000 votes as he won the county again in 2020 over Joe Biden.

Geography

According to the United States Census Bureau, the county has an area of 5,519 square miles (14,290 km²), of which 5,514 square miles (14,280 km²) is land and 5.1 square miles (13 km²) (0.1%) is water.^[24] The lowest point in the state of Arizona is on the Colorado River in San Luis in Yuma County, where it flows out of Arizona and into Sonora in Mexico.

Yuma County is in the west, and northwestern regions of the north–south Sonoran Desert that extends through Sonora state of Mexico to the border of northern Sinaloa state. West of the county across the Colorado River in southeast California is the Colorado Desert, (a northwestern subregion of the Sonoran Desert). North of the county, with La Paz County the regions merge into the southeastern Mojave Desert. Southwest of Yuma County, is the entirety of Northwest Mexico, at the north shoreline of the Gulf of California, and the outlet of the Colorado River into the Colorado River Delta region, now altered with lack of freshwater inputs. Notable mountains in Yuma County include the Gila Mountains and the Tule Mountains.

Adjacent counties and municipalities

Major highways

• Interstate 8
• Historic U.S. Route 80
• U.S. Route 95
• Arizona State Route 195

National protected areas

• Cabeza Prieta National Wildlife Refuge (part)
• Imperial National Wildlife Refuge (part)
• Kofa National Wildlife Refuge (part)

Climate