Pennsylvania Route 416 (PA 416) is an 17-mile (27 km) long state highway located in Franklin county in Pennsylvania. The southern terminus is at the Maryland state line near Nova. The northern terminus is at US 30 in St. Thomas Township.

PA 416 begins at the Maryland border in Montgomery Township, heading northwest on two-lane undivided Mercersburg Road. The road continues into Maryland as Cearfoss Pike, which eventually becomes MD 58. From the state line, the route heads through a mix of farms and woods with some homes, passing through the community of Nova. PA 416 continues into open farmland and intersects PA 995 in Welsh Run. The route continues northwest before making a curve to the northeast and reaching an intersection with PA 16. At this point, PA 416 turns west to form a concurrency with PA 16 on Buchanan Trail, heading northwest through more agricultural areas. The road continues to Mercersburg, where PA 75 joins and it heads into residential areas. The three routes turn north onto Main Street and passes homes and businesses in the center of Mercersburg. In the northern part of town, PA 16 heads to the northwest with PA 75 and PA 416 continuing northeast on Fort Loudon Road. The road passes a few residential and commercial areas before crossing into Peters Township and heading into agricultural surroundings. PA 416 splits from PA 75 by continuing northeast on Mercersburg Road. The road crosses the West Branch Conococheague Creek and passes through the community of Markes. PA 416 passes through more open farmland as it continues into St. Thomas Township and reaches its northern terminus at US 30.

The entire route is in Franklin County.