PA 305 begins at an intersection with US 22 in Porter Township, Huntingdon County, heading north on two-lane undivided Bridge Street.

PA 305 heads back into Porter Township and turns northeast onto Juniata Valley Pike, entering agricultural areas with occasional homes.

The route crosses the Little Juniata River into Logan Township and comes to a bridge over Norfolk Southern's Pittsburgh Line, turning east onto West Diamond Street.

[1][2] In the residential community of Mooresville, PA 305 turns southeast onto Greenwood Road and winds through open farmland with some homes, crossing into Barree Township.

[1][2] At the top of the mountain, PA 305 crosses into Union Township in Mifflin County and leaves the boundaries of Rothrock State Forest.