Surprise is a city in Maricopa County, Arizona, USA. The population was 30,848 at the 2000 census, however rapi growth has boosted the city's population to 85,914 by 2006, according to Census Bureau estimates. As such, it is the second fastest-growing municipality in the greater Phoenix metropolitan area (after Gilbert), and between 1990 and 2000, it was the sixth fastest-growing place among all cities and towns in Arizona.