PA 274 was designated in 1928 to run from PA 75 in Doylesburg east to PA 5 (now PA 34) in New Bloomfield while PA 5 was designated onto the road between New Bloomfield and Duncannon, running concurrent with PA 33 between Mecks Corner and Duncannon. In 1937, PA 274 was extended east from New Bloomfield to PA 14 (later US 11/US 15) in Duncannon, replacing those portions of PA 5 and PA 33. The eastern terminus at US 11/US 15 was rebuilt into an interchange in the 1950s.