Ona is a small unincorporated community along US 60 in Cabell County, West Virginia, United States. It is situated roughly halfway between the towns of Barboursville to the west and Milton to the east. It has a population of 4,512 and spans over a radius of 28.06 square miles. Ona 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.