[6][7] As PA 31 progresses through Mount Pleasant, it forms a concurrency with Pennsylvania Route 981.

[14] Immediately after entering Somerset, PA 31 intersects Pennsylvania Route 281 and forms a concurrency on one-way pairs.

[15] Past the downtown area, PA 31 weaves through the Pennsylvania Turnpike and passes over U.S. Route 219.

[17] After this intersection, PA 31 generally parallels the Turnpike and winds through hilly terrain, passing through Allegheny Township on its way east.

[18] As PA 31 nears Manns Choice, it intersects Pennsylvania Route 96 and is concurrent for 1.81 mi (2.91 km).

[20] The portion of the highway that runs through Mount Pleasant borough is said to have evolved from a Native American path that predated European settlers.

With the coming of European settlers, it became an important access road to the western wilderness and to more settled areas to the east.

The road would become PA 31 and would go through the towns of West Newton, Mount Pleasant, Monongahela, and Washington that had also organized underground railroad stations.

In September 1964, the western terminus of PA 31 was truncated to its current location at the intersection of Mount Pleasant Road and Greensburg Pike in West Newton.

Established in 1994, the winery is the place where visitors are offered samples of the award-winning wine varieties.