It was originally formed by the United States Census Bureau in 1950 and consisted of the Kentucky county of Jefferson and the Indiana counties of Clark and Floyd. As surrounding counties saw an increase in their population densities and the number of their residents employed within Jefferson County, they met Census criteria to be added to the MSA. Jefferson County, Kentucky (contiguous with Louisville Metro), plus twelve outlying countiesseven in Kentucky and five in Southern Indianaare now a part of this MSA. One other Kentucky county was part of the MSA in the 2000 and 2010 U.S. Censuses, but was spun off by the Census Bureau into its own Micropolitan Statistical Area in 2013.