Pennsylvania Route 108 (PA 108) is a highway in Western Pennsylvania that runs for from the Ohio state line near SNPJ to PA 8 in Adams Corner. PA 108 intersects Interstate 376 (I-376) near New Castle and U.S. Route 19 (US 19) near Harlansburg. PA 108 also has an interchange with Interstate 79 (I-79) at exit 105. Route description PA 108 begins at the Ohio border in North Beaver Township, Lawrence County, where the road continues southwest into that state as CR 8 in Mahoning County, providing access to Ohio State Route 170 (SR 170) and SR 617. From the state line, the route heads northeast on two-lane undivided Mt. Jackson Road, passing through farmland with some woods and homes. The route skirts the northern border of the borough of S.N.P.J. in three places, curving more to the east-northeast. PA 108 continues through more rural areas of North Beaver Township, coming to an intersection with PA 551. At this point, the route turns north to form a concurrency with PA 551, remaining Mt. Jackson Road. The road curves northeast through more agricultural areas with some woodland and residences, turning more to the east into wooded areas with some homes. In the community of Mount Jackson, PA 551 splits from PA 108 by heading north along with PA 317. The route continues east-northeast through more farmland and woodland before passing through rural residential areas and coming to an interchange with I-376, becoming a divided highway at this point. Past this interchange, the road becomes undivided again and passes more homes before heading through woods and turning southeast, crossing the Mahoning River. Here, PA 108 becomes the border between Taylor Township to the west and the city of New Castle to the east as it passes commercial establishments and comes to an intersection with PA 18. At this point, the route turns northeast to join PA 18 on Montgomery Avenue, fully entering New Castle and crossing Norfolk Southern's Youngstown Line. The road continues east into residential areas, with the two routes turning northeast onto South Liberty Street. PA 18/PA 108 passes under CSX's New Castle Subdivision railroad line and becomes North Liberty Street, running past a mix of homes and businesses before passing under the US 422 freeway. The road continues through woodland and homes before heading into more residential areas. The two routes turn east onto Mahoning Avenue and head through