Leslie County is located in the U.S. state of Kentucky. Its county seat and largest city is Hyden. As of the 2020 census, the population was 10,513. It was formed in 1878 from portions of Clay, Harlan, and Perry counties, and named for Preston Leslie, governor of Kentucky from 1871 to 1875.

Hyden is a home rule-class city in and the county seat of Leslie County, Kentucky, United States. The population was 365 at the 2010 census. It is located at the junction of U.S. Route 421 and Kentucky Route 80, along the Middle Fork of the Kentucky River.