High Quality Content by WIKIPEDIA articles! Yuma is a city in and the county seat of Yuma County, Arizona, United States. 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 winter visitors make Yuma their winter residence.