Pennsylvania Route 997 is a 49-mile (79 km) route in Franklin and Cumberland Counties. The route begins at the Maryland state line south of Waynesboro and ends at Pennsylvania Route 233 in McCrea. The route was originally signed in 1928 from Waynesboro to Pennsylvania Route 433. Both termini, however, have been adjusted northward and southward. The route is concurrent with two state routes, 16 and 641, and one U.S. Route, Route 30. The route was assigned in 1928 up to U.S. Route 30 in Greenwood. The route was extended several times and has been on its current alignment since 1977.

Route 997 begins at the Maryland state line south of the town of Waynesboro. The route heads northward, crossing East Branch and entering Waynesboro. There, Route 997 becomes concurrent with Pennsylvania Route 16. At the point where Route 997 turns to the north, Route 316 intersects with SR 997. Route 997 heads northward, leaving Waynesboro and Route 16 behind. The highway intersects with and enters Quincy. The highway leaves Quincy and continues northward towards Caledonia.

Route 997 parallels Route 316 and enters the town of Mont Alto, where it intersects with the western terminus of Pennsylvania Route 233. After crossing through Mont Alto and nearby Pond Bank, Route 997 intersects with U.S. Route 30 in Fayetteville. The two routes are concurrent for a short distance in the town of Greenwood. Route 997 heads to the northwest and intersects with Pennsylvania Route 696, which parallels Interstate 81. Route 997 interchanges at Exit 20 of Interstate 81 soon after. The highway enters Scotland and leaves without intersecting with any state highways.

Soon afterwards, U.S. Route 11 intersects in the Greene Township village of Greenvillage. Route 997 continues to the northwest, intersecting with PA 533 and PA 641 (in Roxbury) before interchanging with Interstate 76 in Newburg at Exit 201. The route continues, now to the northeast, and passes Green Spring, a hunting region. Route 997 comes to an end at Pennsylvania Route 233 in McCrea, a route it previously intersected in Mont Alto.

Route 997 was signed in 1928 from Waynesboro to US 30 in Fayetteville. The southern terminus was changed to the state line in 1936 and the northern terminus was changed from Fayetteville to Greenvillage. In 1941, Route 997 was shifted off the present PA 316 alignment to its current alignment. Twenty-three years later, the northern terminus was shifted northward from Greenvillage to its current end in McCrea. In 1977, Route 997 was swapped off its alignment on Mont Alto Road, Main Street and Mount Pleasant Road onto its current route.

Pennsylvania Route 997 Truck is a 3-mile large vehicles route in rural Franklin County, Pennsylvania. It was signed in 1980 along U.S. Route 11 and Pennsylvania Route 433. The route ends at 433 and 997 in Letterkenney Township.