Along the way, US 122 passed through Parkesburg, Honey Brook, Morgantown, Reading, Hamburg, Schuylkill Haven, Pottsville, Frackville, Ashland, Centralia, Mount Carmel, Shamokin, and Sunbury.

This route description features US 122 as it existed in 1950, with references to today's highways to provide context.

The route headed north as Limestone Road before it came to Parkesburg, where it became Church Street and intersected PA 372.

US 122 split from US 30 by turning north onto two-lane Octorara Trail, once again following the present-day alignment of PA 10.

The route continued north and reached Compass, where it turned northwest for a short concurrency with PA 340 along Kings Highway.

At this point, the route turned northeast to form a concurrency with PA 23 on Main Street, crossing into Berks County.

In Leesport, US 122 turned to the northwest as Centre Avenue and intersected PA 383, which headed southwest along Wall Street.

The route left Leesport and continued north along Pottsville Pike a short distance to the east of the Schuylkill River.

US 122 turned northwest onto Port Clinton Avenue and left Hamburg, heading parallel to the Schuylkill River.

The road left Port Clinton and became Centre Turnpike, crossing the Little Schuylkill River before it reached a junction with PA 895 in Molino.

Farther north, US 122 split from present-day PA 61 by turning northwest onto Center Street, crossing the Schuylkill River.

After leaving St. Clair, the route continued north along current PA 61 again, following an unnamed multilane road north-northwest to Frackville.

The route deviated again from present-day PA 61 as it headed onto an alignment that is now closed because of the Centralia mine fire.

At this point, PA 54 became concurrent with US 122 and the two routes turned north on Market Street and west on East Avenue.

PA 54 split from US 122 by turning to the north while US 122 continued west and passed through Kulpmont on Chestnut Street.

The route continued west as an unnamed multilane road and entered Shamokin, where it headed northwest on Mt.

US 122 came to an intersection with the northern terminus of PA 125 and turned northwest onto Sixth Street, leaving Shamokin.

The route passed through Stonington and briefly became a multilane road before narrowing back to two lanes.

[4] The portion of US 122 along Limestone Road in Chester County was originally a Native American trail.

[9] With the creation of the U.S. Highway System in 1926, the road between Reading and Northumberland was designated as part of US 120, a route that ran from Philadelphia northwest to Erie.

[1][2][13] US 122 was rerouted to bypass Orwigsburg to the southwest by 1940, having previously followed Brick Hill Road, Market Street, and present-day PA 443 through the town.

In the 1930s, US 122 was widened to a multilane road between Reading and Leesport, from a point north of Shoemakersville to Hamburg, between a point south of Schuylkill Haven and Pottsville, for a short distance south of Frackville, and for a short distance north of Shamokin.

[15] In the 1950s, US 122 was upgraded to a divided highway from Schuylkill Haven through Pottsville to south of St. Clair, being realigned to bypass Mount Carbon.