Hamlin, originally named "Hamline," is a town in Lincoln County, West Virginia, United States, along the Mud River. The population was rec…Hamlin, originally named "Hamline," is a town in Lincoln County, West Virginia, United States, along the Mud River. The population was recorded as 1,040 at the 2020 census. It is the county seat of Lincoln County. Hamlin is a part of the Huntington-Ashland, WV-KY-OH, Metropolitan Statistical Area. As of the 2010 census, the MSA had a population of 287,702. New definitions from February 28, 2013 placed the population at 363,000.