Gilbert is a large town in Maricopa County, Arizona, United States. It was founded on July 6, 1891 as a rail siding for Arizona Eastern Railway, and the town that sprang up around it was incorporated as the Town of Gilbert in 1920. Gilbert received its name from William "Bobby" Gilbert, the owner of the property that the rail siding was built on. From 1911 through the 1920s, Gilbert was known as the Hay Capital of the World.
In 2007, the US Census Bureau estimated that population of the town was 207,550. Although it is large and growing rapidly, Gilbert is still incorporated as a town rather than as a city. Gilbert was also the fastest-growing place among all cities and towns in Arizona of any size between 1990 and 2000. The center of population of Arizona is located in Gilbert.