The northern terminus was realigned to Hughesville by 1960, the same time a portion of the route from Saylorsburg to Wind Gap was relocated to a freeway alignment.

PA 115 begins at a roundabout with US 209 in the community of Brodheadsville in Chestnuthill Township, Monroe County, which is in the Pocono Mountains region.

From this intersection, the route heads northwest as a two-lane undivided road, running through business areas and passing north of Pleasant Valley High School before continuing into a mix of farmland and woodland with some development.

The road passes to the southwest of Pocono Raceway and gains a center left-turn lane before it curves more to the west and meets the northern terminus of PA 903.

Here, the route immediately reaches a partial cloverleaf interchange with I-80 at exit 284, at which point it widens into a four-lane divided highway.

The route passes through more dense forest, curving more to the west and entering Bear Creek Township in the community of Shades Glen.

Here, PA 115 gains a center left-turn lane and heads through wooded areas of homes, passing to the south of Bear Creek Lake.

[3][5] PA 115 curves northwest and comes to a ramp that provides access to I-476 (Pennsylvania Turnpike Northeast Extension) at exit 105 (Wilkes-Barre interchange).

The road curves northeast, coming to a northbound pullover for overweight trucks, before a turn to the northwest, where it passes under I-476.

PA 115 continues north through forests with some homes, coming to a northbound runaway truck ramp and passing through Llewellyns Corners.

The route enters Plains Township and passes over the Reading Blue Mountain and Northern Railroad's Lehigh Division line as it comes to another northbound runaway truck ramp and winds through more dense forests as a four-lane divided highway.

Past this interchange, the roadway continues west as a freeway called the North Cross Valley Expressway, which is part of PA 309.

George Washington ordered Sullivan to march upstream the Susquehanna River to join General James Clinton's brigade at the Bradford County town of Tioga (now known as Athens).

[7] At the turn of the 19th century, the population and economy of Luzerne County continued to grow and there was a necessity for new roads to improve communication between distant settlements.

This led Arnold Colt, a Luzerne County clerk, to construct a turnpike directly connecting the Wyoming and Lehigh Valleys on Sullivan's Trail.

[10][11] They are building a plank road to Slocum Hollow [now Scranton] to get to a railroad and they say that a man can get from Wilkes-Barre to New York in a day.

The new railroad shortened the time required to ship goods between the two endpoints from ten days (by way of roads) to just one.

[18][19] When PA 115 was commissioned in 1928, the road was mostly aligned east–west and stretched from US 220 in Montoursville east to US 611 in Swiftwater near Mount Pocono.

The same year, the northern terminus was moved from Montoursville to PA 54 in the Montour County community of Mausdale.

In addition, the route was moved to its new alignment between Lehman and Dallas, where it turned southeast and picked up a concurrency with US 309.