Polk City is a city in Polk County, Florida, United States. It is part of the Lakeland–Winter Haven metropolitan statistical area. Its population w…Polk City is a city in Polk County, Florida, United States. It is part of the Lakeland–Winter Haven metropolitan statistical area. Its population was 2,713 at the 2020 census. Polk City was incorporated as the Town of Polk City in 1925, and changed by ordinance to the City of Polk City in 2005. The city was named after the county, itself named after James Knox Polk, the 11th President of the United States.