In 1984, the Pennsylvania Department of Transportation (PennDOT) proposed extending US 222 from I-78/PA 309 to Center City Allentown, where it would end at PA 145.

After passing the amusement park, the route splits into two carriageways, with PA 222 north remaining on Hamilton Boulevard and PA 222 south following the newer Hamilton Boulevard Bypass to the north; at the split, there is a pair of median U-turn ramps.

To the east, the road intersects Cedar Crest Boulevard, a major north–south arterial in the Lehigh Valley area.

[3][4] PA 222 heads into Center City Allentown, where it splits into a one-way pair at 12th Street.

Southbound PA 222 passes to the north of the PPL Center sports arena, where the Lehigh Valley Phantoms of the American Hockey League play, between 8th and 7th streets.

[3][4] From the establishment of Allentown in the 18th century to the modern age, Hamilton Street has been the main arterial of the municipality.

Following an economic depression in the late 19th century, Allentown rebounded briefly in the early 20th century, establishing many shopping stores along Hamilton Street, the commercial center of the city, which hosted the annual Workhorse Parade, was a popular attraction in the 1910s.

One of those highways was Legislative Route 157, the modern Hamilton Boulevard section of PA 222, west of Allentown.

Another state highway was Legislative Route 159, aligned east of Allentown to downtown Bethlehem along Hanover Avenue and Broad Street.

[10] PA 43 was aligned as a bypass, north of the Pennsylvania Dutch Country, between Allentown and Harrisburg.

After the plan was introduced, he said that motorists might be aided if US 222 is extended along Hamilton Boulevard to connect with the proposed PA 145 corridor.

[19] PennDOT originally planned the road as US 222 but AASHTO denied the extension, stating that the route "is not the shortest or best available route between major control points on the system, and therefore, does not adhere to the policies established under AASHTO's 'Purpose and Policy Statement for U.S. Numbered Highways'".