Putnam County is a county in the U.S. state of West Virginia. As of the 2020 census, the population was 57,440. Its county seat is Winfield, its largest incorporated city is Hurricane, and its largest community is the census-designated place of Teays Valley. Putnam County is part of the Huntington–Ashland, WV-KY-OH Metropolitan Statistical Area, across the Kanawha River from Charleston, West Virginia.