Gilbert is a town in Maricopa County, Arizona, United States, located southeast of Phoenix within the city's metropolitan area. Incorporated on July 6, 1920, Gilbert was once known as the "Hay Shipping Capital of the World". The population was 267,918 at the 2020 census, and was estimated to be 275,346 in 2022. It is the fifth-largest municipality in Arizona, and the fourth-largest in the Phoenix metro area. It covers an area of nearly 69 square miles (179 km2). Gilbert has made a rapid transformation from an agriculture-based community to an economically diverse suburban center located in the southeastern valley of the Greater Phoenix area. It has grown at an extremely high rate over the last three decades, increasing in population from 5,717 in 1980 to 267,918 as of the 2020 census. The town grew at an average annual rate of over 10% during this 40-year period. It is the largest incorporated town in the United States.