Clementsville is an unincorporated community in western Casey County, Kentucky, United States.

This community grew up around the third-oldest Roman Catholic settlement in the Archdiocese of Louisville where seven Catholic families, originally from Maryland, migrated from Washington County, Kentucky to the Casey Creek region (an area close to Clementsville) in 1802 and established what would later become the church and parish of Saint Bernard Catholic Church (so named for St. Bernard of Clairvaux).

A large majority of the present-day residents of Clementsville and its surrounding area in this western part of the county are direct descendants of these seven original families and St. Bernard Church continues to be the focal point and "heartbeat" of Clementsville.

Lyons states, "It is a story of hardy pioneers and their descendants, of valiant missionaries and their successors, whose labors form one of the most interesting chapters in the history of Catholicity in Kentucky."

The Clementsville area is also the only place in Casey County that has an airplane landing strip.