Bullitt County is a county located in the north central portion of the U.S. state of Kentucky. As of the 2020 census, the population was 82,217. Its county seat is Shepherdsville. The county was founded in 1796. Located just south of the city of Louisville, Bullitt County is included in the Louisville/Jefferson County, KY-IN Metropolitan Statistical Area, commonly known as Kentuckiana. The western fifth of the county is part of the United States Army post of Fort Knox and is reserved for military training.

Shepherdsville is a home rule-class city on the Salt River in Bullitt County, Kentucky, in the United States. It is the second largest city and seat of its county, located just south of Louisville. The population was 14,201 during the 2020 U.S. Census.