Flemingsburg is a home rule-class city in Fleming County, Kentucky, in the United States. The population was 2,953 at the 2020 census, up fro…Flemingsburg is a home rule-class city in Fleming County, Kentucky, in the United States. The population was 2,953 at the 2020 census, up from 2,658 at the 2010 census. It is the seat of Fleming County.