Allen County is a county located in the U.S. state of Kentucky. As of the 2020 census, the population was 20,588. Its county seat and only municipality is Scottsville. The county is named for Colonel John Allen, a state senator and soldier who was killed leading the 1st Regiment of Kentucky Rifleman at the Battle of Frenchtown, Michigan during the War of 1812. Allen County was a dry county until 2023, when it voted to legalize the sale of alcohol. It was formed in 1815 from parts of Barren and Warren counties. Allen County is included in the Bowling Green, KY Metropolitan Statistical Area.

Scottsville is a home rule-class city in Allen County, Kentucky, in the United States. It is the seat of its county. The population was 4,299 during the 2020 United States Census.