Yuma County, Arizona  Yuma County is a county in the southwestern corner of the U.S. state of Arizona. As of the 2010 census, its population was 195,751. The county seat is Yuma. 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. 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. The county territory was defined as being west of longitude 113° 20' and south of the Bill Williams River. 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. Agriculture is a $3 billion business annually, employing tens of thousands of workers but at minimum wages. During the winter agricultural season from November to March, some 40,000 Mexican workers cross the border daily to work in United States fields. The area is watered by the Colorado River, and the sector supplies a large part of the US leafy vegetables. The Yuma Lettuce Days festival and agritourism is connected to Yuma agriculture. 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..." 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 illegal foreign nationals were apprehended in the area, a 46% increase over the previous year. In 2015, however, only 6,000 people were apprehended, as the border was fortified and augmented.