Mesa (māˈsə) [key], city (1990 pop. 288,091), Maricopa co., S central Ariz., in the irrigated Salt River valley; inc. 1883. Electronic components, fabricated metals, aircraft, and machine tools are among its various manufactures. One of the fastest-growing U.S. cities, Mesa's population has more than doubled since 1980. Tourism is important, and the citrus and farm products of the area are packed and processed in Mesa. The Mormons who founded the city in 1878 used old Native American irrigation canals for farming in the Salt River valley. In Mesa are the Mesa Art Center, a Mormon temple, and the chief agricultural experiment farm of the Univ. of Arizona. The Chicago Cubs baseball team also has a spring training camp there.