Yuma (Cocopah: Yuum) is a city in and the county seat of Yuma County, Arizona, United States. It is located in the southwestern corner of the state, and the population of the city was 77,515 at the 2000 census, with a 2008 Census Bureau estimated population of 90,041.
Yuma is the principal city of the Yuma, Arizona Metropolitan Statistical Area, which consists of Yuma County. According to the United States Census Bureau, the 2008 estimated population of the Yuma MSA is 194,322, though more than 85,000 retirees make Yuma their winter residence.
The area's first settlers were Native American tribes whose descendants now occupy the Cocopah and Quechan reservations. In 1540, expeditions under Hernando de Alarcon and Melchior Diaz visited the area and immediately saw the natural crossing of the Colorado River as an ideal spot for a city, as the Colorado River narrows to slightly under 1000 feet wide in one small point. Later military expeditions that crossed the Colorado River at the Yuma Crossing include Juan Bautista de Anza (1774), the Mormon Battalion (1848) and the California Column (1862).