The route begins in Lawrence County where US 422 meets the Ohiostate line; PA 208 heads east-northeastward to the village of New Bedford about a mile from the state line. The route junctions with the former PA 932 in the village and was the former alignment of US 422 from the state line to this point, where the old alignment turned southeast; PA 208 continues eastward here. About later, it is joined by PA 551 and the concurrency turns northward for about before turning east again as it crosses the Shenango River and enters the village of Pulaski. The concurrency ends later, and PA 208 continues another to its interchange with Interstate 376. From here, the route heads into a rural area of northern Lawrence County that is home to an Amish community. The road continues another east, where it junctions with PA 18 about west of the borough of New Wilmington, which the route enters shortly thereafter. In the borough, PA 158 joins briefly, and then leaves the route at the northern terminus of PA 956. PA 208 passes north of Westminster College before it leaves the borough and continues eastward about to the borough of Volant, where, at the east end of the borough, the route intersects with the northern terminus of PA 168 and turns northeast and crosses the county line later. As PA 208 enters Mercer County, it turns east-northeast and meets US 19 at the village of Leesburg about later. The routes briefly overlap northward, and then PA 208 continues east-northeastward. About from Leesburg, the route is joined by PA 258 north of the Grove City Premium Outlets, and the concurrency then interchanges with I-79 immediately thereafter. The concurrency ends later at the village of London – prior to the interstate, this was a simple junction between PA 208 and PA 258. PA 208 continues east-northeast about to the borough of Grove City, where it meets PA 58 and PA 173. This point is the westernt terminus of the PA 58/PA 173 concurrency, and the southern terminus of the PA 173/PA 208 concurrency; also at this point, the north- and southbound lanes of the PA 173/PA 208 concurrency are split on one-way streets through the downtown area of Grove City, heading northward for about. Another later, the concurrency ends, and PA 208 continues eastward, leaves the borough, and meets the county line later. PA 208 enters Venango County, and later intersects with PA 8 in the borough of Barkeyville. The route continues eastward where it passes over I-80 before entering the borough of Clintonville later; here the route intersects with PA 308. About later, or west of the borough of Emlenton, the route is joined by PA 38; this route, just south of this intersection, meets I-80. The concurrency meets the northern terminus of PA 268 about later in the borough, and turns north to cross the Allegheny River. The concurrency turns east at the center of the town, then crosses into Clarion County later, winding northward, eastward, and finally east-northeastward, crossing back into Venango County again later. The concurrency meets the northern terminus of PA 478 later; just south of this intersection, PA 478 has a partial interchange with I-80 for traffic exiting or entering eastbound. The westbound interchange ramps are 0.3 eastward on the PA 38/PA 208 concurrency, which continues northeasterly to the county line later. After crossing into Clarion County a second and final time, the PA 38/PA 208 concurrency continues north-northeastward before its northern terminus. PA 208 turns eastward and winds to the borough of Knox, where the route turns south and then east again, intersecting with PA 338 about from the center of the borough. Continuing east-northeast, the route travels to the borough of Shippenville, where it meets US 322. The two routes overlap for eastward, where PA 208 turns north, traveling to the village of Fryburg. Here, the route intersects with the eastern terminus of PA 157, and PA 208 turns northeastward for about, then turns north again, where it terminates about later in the village of Frills Corners at PA 36.
History
1926-1948 – segment from the Ohio state line to New Bedford was designated US 422.
1928 – signed PA 208 from Barkeyville to west of Emlenton.
1928-1929 – segment from Pulaski to New Wilmington was designated PA 218.
1932-1936 – segment from Volant to Leesburg was designated PA 956.
1936 – western terminus of PA 208 moved from Barkeyville to PA 158 via Leesburg Station Rd.
1936-1959 – segment from Volant to Leesburg was changed to PA 168.
1926-1948 – segment from the Ohio state line to Pulaski was designated PA 278.
1928-1959 – segment from Mariasville to Shippenville was designated PA 238.
1929-1959 – segment from Pulaski to Volant was designated PA 278.
1927-1968 – segment from Shippenville to Frills Cors was designated PA 66.
1959 – western terminus of PA 208 moved to its current location, and eastern terminus was moved from PA 38 west of Emlenton to Shippenville.
1968 – eastern terminus of PA 208 moved to its current location.
PennsylvaniaRoute 208 Truck is a truck route around a weight-restricted bridge over the Doe Creek on which trucks over 20 tons and combination loads over 26 tons are prohibited. The route follows US 422 and PA 551. The route was signed in 2013.