PA 915 begins at an interchange with I-70 in Brush Creek Township, Fulton County, heading northeast on two-lane undivided Crystal Springs Road, after sharing a brief concurrency with Old 126.

At this point, the route turns east to form a concurrency with US 30 on Lincoln Highway, heading into Buchanan State Forest.

The road curves to the northeast and passes over I-76 (Pennsylvania Turnpike), crossing into Wells Township.

The route winds north through more forests before heading into agricultural areas and turning to the northwest.

The road heads into the borough of Hopewell and becomes Water Street, running between the Raystown Branch Juniata River to the west and homes to the east.