Bethlehem is a town in Litchfield County, Connecticut, United States. The population was 3,385 at the 2020 census, down from 3,607 at the 2010 census. The town center is a historic district and a cens…Bethlehem is a town in Litchfield County, Connecticut, United States. The population was 3,385 at the 2020 census, down from 3,607 at the 2010 census. The town center is a historic district and a census-designated place.