PA 85 begins at an intersection with
PA 28/
PA 66 in
Rayburn Township,
Armstrong County, heading east on a two-lane undivided road. The route passes through agricultural areas with some homes, running through the community of Green Acres. The road crosses the
Cowanshannock Creek and heads through the community of Sunnyside, continuing northeast through woods and farms with some homes to the north of the creek and crossing into
Valley Township. PA 85 curves southeast and winds east through wooded areas with occasional residences, passing through
Greendale. The route heads through a mix of agriculture and woodland with some homes, continuing into
Cowanshannock Township. The road runs through rural residential areas, passing through Rose Valley and
Yatesboro. PA 85 crosses into the borough of
Rural Valley and passes between housing areas to the north and woods to the south. The route crosses back into Cowanshannock Township and continues through a mix of farmland and woodland, passing to the south of the residential communities of Meredith and Nu Mine. The road intersects
PA 839 and runs northeast and east through more rural areas. The route runs through farmland and turns southeast at Hoosicks Mill. PA 85 enters
South Mahoning Township in
Indiana County and runs southeast through more farms and woods with a few homes, coming to an intersection with
PA 210. At this point, the route turns east for a
concurrency with PA 85, coming to a junction with
PA 954. Here, PA 954 turns east to join PA 85/PA 210. The three routes run through the residential community of
Beyer before passing through more rural areas prior to entering the borough of
Plumville. Here, the road becomes Main Street and passes homes and businesses. PA 954 splits from PA 85/PA 210 by turning north Smicksburg Street and PA 85/PA 210 continue northeast through more of the town. The road turns to the southeast and heads back into South Mahoning Township, becoming unnamed again. PA 210 splits from PA 85 by heading northeast, and PA 85 continues southeast through more farmland and woodland with a few residences, curving south. The road heads southeast into
Washington Township, turning more to the east-southeast. The route continues into
Rayne Township and runs through more wooded areas with some fields and homes. PA 85 comes to its eastern terminus at an intersection with
US 119 in
Home. ==Major intersections==