Middleburg, FL
Middleburg is an unincorporated area and census-designated place CDP within Clay County in the U.S. state of Florida, located 26 miles 42 km southwest of downtown Jacksonville and 16 miles 26 km northwest of Green Cove Springs, the county seat of Clay County. As of the 2020 census, the population of Middleburg was 12,881, down from 13,008 at the 2010 census. It is part of the Jacksonville, Florida Metropolitan Statistical Area. Source: Wikipedia