Monticello is the only city and the county seat of Jefferson County, Florida, United States. The city is named after Monticello, the estate of the county's namesake, Thomas Jefferson, on which the Jefferson County Courthouse was modeled. The population was 2,589 at the 2020 census. It is part of the Tallahassee, Florida Metropolitan Statistical Area. Monticello is home to Indian mounds and many historic buildings, including the Perkins Opera House and Monticello Old Jail Museum.