Bell County is a county located in the southeast part of the U.S. state of Kentucky. As of the 2020 census, the population was 24,097. Its county seat is Pineville and its largest city is Middlesboro. The county was formed in 1867, during the Reconstruction era from parts of Knox and Harlan counties and augmented from Knox County in 1872. The county is named for Joshua Fry Bell, a US Representative.