Putnam County is a county located in the northern part of the state of Florida. As of the 2020 census, the population was 73,321. Its county seat is Palatka. Putnam County comprises the Palatka, Florida Micropolitan Statistical Area, which is included in the Jacksonville—Kingsland—Palatka, Florida—Georgia Combined Stati…Putnam County is a county located in the northern part of the state of Florida. As of the 2020 census, the population was 73,321. Its county seat is Palatka. Putnam County comprises the Palatka, Florida Micropolitan Statistical Area, which is included in the Jacksonville—Kingsland—Palatka, Florida—Georgia Combined Statistical Area. The county is centrally located between Jacksonville, Gainesville, St. Augustine, and Daytona Beach.