The road heads through a mix of farmland and woodland with some homes before ascending forested Conococheague Mountain.

[2][3] The route heads into the Tuscarora State Forest and enters Toboyne Township in Perry County and becomes an unnamed road, making a hairpin turn to the southwest before another hairpin turn to the northeast to descend the mountain, passing by Big Spring State Park.

The route heads into the borough of Blain and passes homes, reaching an intersection with PA 17 and turns southeast onto Main Street.

PA 274 curves to the east and heads back into Jackson Township, turning northeast into more open farmland as an unnamed road.

From here, the route heads east-northeast through areas of farms with homes, coming to an intersection with the northern terminus of PA 233 in Green Park.

Past this intersection, PA 274 heads south of West Perry High School and continues through more agricultural areas with some residences, passing through Elliottsburg and Dunn.

The road continues through more agricultural areas with some woodland and residences, heading southeast and passing through Roseglen.

The route becomes the border between the borough of Duncannon to the north and Penn Township to the south before ending at an interchange with the US 11/US 15 freeway, where the road also crosses the Appalachian Trail.

[8] In the 1950s, the eastern terminus at US 11/US 15 was rebuilt into an interchange as part of construction of a bypass carrying US 11/US 15 around Duncannon.