About This Place
Middleburg is a census-designated place (CDP) in Clay County, Florida, United States, located 29 miles southwest of downtown Jacksonville, Florida, 16 miles northwest of Green Cove Springs, Florida, and home to Middleburg High School. The population was 13,008 at the 2010 census.
Middleburg is located at 30°3′3″N 81°54′7″W / 30.05083°N 81.90194°W / 30.05083; -81.90194 (30.050783, -81.902013).
According to the United States Census Bureau, the CDP has a total area of 18.3 square miles (47.3 km²), all of it land.