Interlachen is a town in Putnam County, Florida, United States. It is part of the Palatka Micropolitan Statistical Area.The population was 1,441 at the 2020 census. The town was named by a gentleman named Mr. Berkelmann from Germany who lived in Interlachen when the town was being incorporated. He said that since the town was located betwee…Interlachen is a town in Putnam County, Florida, United States. It is part of the Palatka Micropolitan Statistical Area.The population was 1,441 at the 2020 census. The town was named by a gentleman named Mr. Berkelmann from Germany who lived in Interlachen when the town was being incorporated. He said that since the town was located between 2 lakes and there were more than 28 lakes in the town, Interlachen, which means "between the lakes" would be an appropriate name.