Baker County is a county in the U.S. state of Florida. As of the 2020 census, the population was 28,259. Its county seat is Macclenny. The county was founded in 1861 and is named for James McNair Baker, a judge and Confederate Senator. Baker County is included in the Jacksonville, Florida Metropolitan Statistical Area. In 1864, the Battle of Olustee, which was the only major American Civil War battle in Florida, was fought near Lake City in Baker County.