Mesa is a city in Maricopa County, in the U.S. state of Arizona and is a suburb of Phoenix, within the Phoenix Metropolitan Statistical Area. It is the third-largest city in Arizona, after Phoenix and Tucson.

Mesa is one of the United States' fastest-growing cities, and currently ranks as the 37th-largest. 2006 Census Bureau estimates put the city's population at 460,155.

The city proper has a larger population than better-known U.S. cities such as St. Louis, Miami, Minneapolis, or Pittsburgh.

Although it has a large population, Mesa is a "bedroom community." Neighborhoods across the city are diverse — some areas have experienced urban blight, while others feature middle class dwellings and elaborate custom homes.

Mesa was founded in January 1878 by Latter-day Saint (or Mormon) pioneers and its population is still roughly one-tenth Mormon. The Church of Jesus Christ of Latter-day Saints operates one of its oldest temples in Mesa (the Mesa Arizona Temple).

The history of Mesa dates back at least two thousand years to the arrival of the Hohokam people. The Hohokam, whose name means "All Used Up" or "The Departed Ones," built the original canal system. The canals were the largest and most sophisticated in the prehistoric New World. Some were up to 90 feet wide and ten feet deep at their head gates, extending for as far as 16 miles across the desert. By A.D. 1100 water could be delivered to an area over 110,000 acres, transforming the Sonoran Desert into an agricultural oasis. By A.D. 1450, the Hohokam had constructed hundreds of miles of canals many of which are still in use today.

After the disappearance of the Hohokam and before the arrival of the early settlers little is known, as explorers did not venture into this area. By the late 19th century near present-day Mesa, U.S. Army troops subdued the Apache opening the way for settlement.

Daniel Webster Jones led an expedition to found a Mormon settlement in Arizona. Leaving St. George, Utah in March 1877, Jones and others arrived at Lehi, an area just north of present-day Mesa. Jones had been asked by LDS officials to direct a party of people in establishing a settlement in Arizona. This settlement was initially known as Jonesville and Fort Utah and did not receive the name of Lehi until 1883, when it was adopted on the suggestion of Brigham Young, Jr.

At the same time, another group dubbed the First Mesa Company arrived from Utah and Idaho. Their leaders were named Crismon, Pomeroy, Robson, and Sirrine. Rather than accepting an invitation to settle at Jones' Lehi settlement, they moved to the top of the mesa that serves as the city's namesake. They dug irrigation canals, some of which were over the original Hohokam canals, and by April 1878, water was flowing through them. The Second Mesa Company arrived in 1879 and settled to the east of where the First Mesa Company settled in 1880, due to lack of available farmland. This settlement was called Stringtown.

On July 17, 1878, Mesa City was registered as a 1-square-mile townsite. 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. The revenues from the company provided enough for capital expenditures until the 1960s. During the Great Depression, WPA funds provided paved streets, a new hospital, a new town hall and a library.

With the opening of Falcon Field and Williams Field in the early 1940s, more military personnel began to move into the Mesa area. With the advent of air conditioning and the rise of tourism, population growth exploded in Mesa as well as the rest of the Phoenix area. The 1950s and 1960s showed growth of commerce and industry, especially from early aerospace companies. As late as 1960, half of the residents of Mesa made a living with agriculture, but this has declined substantially as Mesa's suburban growth continued on track with the rest of the Phoenix metro area.