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 93,064 at the 2010 census, increased from the 2000 Census Bureau population of 77,515.

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).

Arizona (ⁱ/ɛrɪˈzoʊnə/; /ærɪˈzoʊnə/) (Navajo: Hoozdo Hahoodzo; O'odham: Alĭ ṣonak) is a state of the United States, located in the southwestern region of the country. Arizona is also part of the Western United States and of the Mountain West states. Arizona is the sixth most extensive and the 16th most populous of the 50 states. Its capital and largest city is Phoenix. The second largest city is Tucson, followed in population by eight cities of the Phoenix metropolitan area: Mesa, Chandler, Glendale, Scottsdale, Gilbert, Tempe, Peoria, and Surprise.

Arizona is the 48th state and last of the contiguous states to be admitted to the Union, and it achieved statehood on February 14, 1912. Arizona is noted for its desert climate in its southern half, where there are very hot summers and quite mild winters. The northern half of Arizona also features forests of pine, Douglas fir, and spruce trees, a very large, high plateau (the Colorado Plateau) and some mountain ranges—such as the San Francisco Mountains—as well as large, deep canyons, where there is much more moderate weather for three seasons of the year, plus significant snowfalls. There are ski resorts in the areas of Flagstaff and Alpine.