Piney Fork is an unincorporated community in central Smithfield Township, Jefferson County, Ohio, United States. Although it is unincorporated, it has a post office, with the ZIP code of 43941. The stream of Piney Fork flows southeast past the community; it meets Short Creek in far western Warren Township, and Short Creek in turn meets the Ohio River at Rayland. Piney Fork is part of the Weirton–Steubenville, WV-OH Metropolitan Statistical Area.