After US 22 was relocated to its present freeway alignment in 1955, the southern terminus of PA 987 was cut back to its interchange with US 22, which used to carry Interstate 78 (I-78) as well.

In the early 2000s, PA 987 was widened into a divided highway and shifted to a new alignment near Lehigh Valley International Airport.

A block west of PA 512, the two routes turn north onto South Chestnut Street, passing homes.

The route curves northwest through a mix of farm fields and homes as it leaves Bath.

The route continues through a mix of farmland and homes before it reaches its northern terminus at PA 946 at the Cross Roads junction near the community of Klecknersville.

[10] Following completion of the US 22 freeway in 1955, the southern terminus of PA 987 was cut back to the interchange with US 22, which also carried I-78 at the time.

[13] In 2000, a two-year project costing $16.8 million began to widen PA 987 to a divided highway between US 22 and Schoenersville Road.