Middleton is a city in Hardeman County, Tennessee, United States. The population was 706 at the 2010 census, up from 602 at the 2000 cen…Middleton is a city in Hardeman County, Tennessee, United States. The population was 706 at the 2010 census, up from 602 at the 2000 census. It is located at the intersection of Tennessee State Route 125 and Tennessee State Route 57. Its slogan is the "Crossroads of the South".