Mesa is a city in Maricopa County, in the U.S. state of Arizona, and is a suburb located about 20 miles (32 km) east of Phoenix. Mesa is the central city of the East Valley section of the Phoenix Metropolitan Area. It is bordered by Tempe on the west, the Salt River Pima-Maricopa Indian Community on the north, Chandler and Gilbert on the south, and Apache Junction on the east. As of the 2010 Census Mesa became Arizona's center of population.

Mesa is the third-largest city in Arizona, after Phoenix and Tucson, and the 38th-largest city in the US. The city is home to 439,041 people as of 2010 according to the Census Bureau. Mesa is home to numerous higher education facilities including the Polytechnic campus of Arizona State University.

On July 17, 1878, Mesa City was registered as a 1-square-mile (2.6 km2) town site. The first school was built in 1879. In 1883, Mesa City was incorporated with a population of 300 people. Dr. A. J. Chandler, who would later go on to found the city of Chandler, worked on widening the Mesa Canal in 1895 to allow for enough flow to build a power plant. In 1917, the city of Mesa purchased the utility company.

As of the census of 2010, there were 439,041 people, 146,643 households, and 99,863 families residing in the city. The population density was 3,171.3 people per square mile (1,224.4/km²). There were 175,701 housing units at an average density of 1,405.7 per square mile (542.8/km²).