The Louisville metropolitan area is the 43rd largest metropolitan statistical area (MSA) in the United States. It had a population of 1,395,855 in 2020 according to the latest official census, and its principal city is Louisville, Kentucky. The metropolitan area 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, plus eleven outlying countiesseven in Kentucky and four in Southern Indianaare now a part of this MSA. Two other counties, one each in Kentucky and Indiana, were part of the MSA in the 2000 and 2010 U.S. Censuses, but were spun off by the Census Bureau into their own Micropolitan Statistical Areas in 2013 and 2018 respectively. The formal name given to the area by the Census Bureau is the Louisville–Jefferson County, Kentucky–Indiana, metropolitan statistical area, though it is regularly referred to as Kentuckiana. It is now the primary MSA of the Louisville/Jefferson County–Elizabethtown–Bardstown, KY-IN Combined Statistical Area, created by the United States Bureau of the Census in 2000 and recently redefined in 2018. The combined statistical area (CSA) adds the counties of Hardin County, Kentucky, LaRue County, Kentucky, Jefferson County, Indiana, and Nelson County, Kentucky and comprises the Louisville–Jefferson County MSA, the Elizabethtown–Fort Knox, Kentucky, MSA, the Bardstown, Kentucky, micropolitan statistical area and the Scottsburg, Indiana micropolitan statistical area. In 2020, the Census Bureau measured the combined statistical area's population at 1,601,309. Definitions , the U.S. Office of Management and Budget defines the Louisville–Jefferson County MSA as including Bullitt, Henry, Jefferson, Meade, Oldham, Shelby, and Trimble Counties in Kentucky and Clark, Floyd, Harrison, and Washington Counties in Indiana. The larger Louisville–Jefferson County–Elizabethtown–Bardstown CSA adds two other statistical areas in Kentucky and one in Indiana: The Elizabethtown–Fort Knox, Kentucky, MSA, consisting of Hardin and LaRue Counties. The Bardstown, Kentucky, micropolitan statistical area, consisting of Nelson County. The Scottsburg, Indiana, micropolitan statistical area, consisting of that state's Scott County. Counties Louisville–Jefferson County MSA Bullitt County, Kentucky (80,246) Clark County, Indiana (116,973) Floyd County, Indiana (77,071) Harrison County, Indiana (39,898) Henry County, Kentucky (16,006) Jefferson County, Kentucky (771,158) Oldham County, Kentucky (66,415) Shelby County, Kentucky (47,421) Spencer County, Kentucky (18,507) Trimble County,