When Pennsylvania legislated routes in 1911, the present alignment of PA 416 was not assigned a number. PA 416 was designated in 1928 to run from PA 16 in Mercersburg northeast to US 30 west of St. Thomas along a paved road. By 1930, the current alignment of the route between the Maryland border and PA 16 east of Mercersburg was an unnumbered, unpaved road. PA 416 was extended south from Mercersburg to the Maryland border southeast of Welsh Run in 1937, following its present alignment. The entire length of the route was paved in the 1930s.
