PA 427 begins at an intersection with US 322 in the borough of Sugarcreek in Venango County, heading northwest on a two-lane undivided road.

PA 427 turns west to cross the creek, curving north into agricultural areas with some woods and residences.

The route continues into Jackson Township and turns northeast to cross Sugar Creek again before making another curve to the north.

The route turns north onto Academy Street and runs between homes the west and the Sugar Creek to the east, curving to the northeast.

The road heads into more wooded areas with some farm fields as it crosses into Plum Township and turns to the northeast.