Mason County is a county located in the U.S. state of Kentucky. As of the 2020 census, the population was 17,120. Its county seat is Maysville. The county was created from Bourbon County, Virginia in 1788 and named for George Mason, a Virginia delegate to the U.S. Constitutional Convention known as the "Father of the Bill of Rights". Mason County comprises the Maysville, KY Micropolitan Statistical Area, which is included in the Cincinnati-Wilmington-Maysville, OH-KY-IN Combined Statistical Area.

Maysville is a home rule-class city in Mason County, Kentucky, United States, and is the seat of Mason County. The population was 8,873 as of the 2020 census. Maysville is on the Ohio River, 66 miles (106 km) northeast of Lexington. It is the principal city of the Maysville Micropolitan Statistical Area, which comprises Mason County. Two bridges cross the Ohio from Maysville to Aberdeen, Ohio: the Simon Kenton Memorial Bridge built in 1931 and the William H. Harsha Bridge built in 2001.