Piney Fork is an unincorporated community in central Smithfield Township, Jefferson County, Ohio, United States. 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.
A Presbyterian church was built at Piney Fork in 1800. A post office called Piney Fork has been in operation since 1902.