Florence is a town in and the county seat of Pinal County, Arizona, United States. The population was 17,054 at the 2000 census; according to 2005 Census Bureau estimates, the population of the town remained unchanged. The largest Arizona State Prison complex, the Florence complex, is located in the city, and its preserved Main Street and open desert scenery was the setting of the major motion picture Murphy's Romance. There are a total of 9 prisons from the county, state, federal and two private prisons. There are 3 state prisons located in Florence. Florence is home to the annual "Country Thunder" music festival.