In 2019, the most populous county located in the state of Kentucky is Jefferson County, home to the city of Louisville, which has a population that’s grown to 770,517 since the last census was taken in 2010. Jefferson County has experienced a growth rate of 3.84%. Other large counties in state of Kentucky include Fayette County (323,780) with the city of Lexington, Kenton County (166,051) with the city of Covington and part of the Cincinnati metro area, Boone County (131,533), Warren County (131,264), Hardin County (110,356), and Daviess County (101,104). Of these counties, Warren County had the most rapid growth of 14.82%.
The county with the lowest population in the state of Kentucky is Robertson County, which has a population of 2,315. Since the last census in 2010, Robertson County has had a growth rate of -6.15%. Following Robertson County, other very small counties in Kentucky are Hickman County (4,421), Owsley County (4,472), and Carlisle County (4,771). All of these counties have experienced a decline in population, the greatest of which occurred in Hickman County with a growth rate of -9.01%.
The county with the most rapid growth in Kentucky is Scott County, which has seen a population growth of 18.51% since the 2010 census, bringing the population up to 56,051 in 2019. Following Scott County are Warren County (14.82%), Shelby County (14.79%), and Jessamine County (10.75%). Martin County has the highest population decrease with a loss of 12.31% of its residents.