As US 19 Truck enters the southern parts of Pittsburgh, its name becomes West Liberty Avenue as it passes through the Beechview neighborhood.

At the south portal of the Liberty Tunnel, US 19 Truck interchanges with Pennsylvania Route 51 (PA 51; Saw Mill Run Boulevard) and joins it, following it north.

After 1.4 miles (2.3 km), US 19 Truck and PA 51 encounter the Penn–Lincoln Parkway, carrying I-376/US 22/US 30, at a complex, unorthodox interchange complex that stretches roughly half a mile (0.80 km) along the parkway and rests just south of the Fort Pitt Tunnel.

The ramp travels for roughly half a mile (0.80 km) in this fashion before making a U-shaped curve.

The Penn–Lincoln Parkway, now with both directions carrying I-376/US 22/US 30/US 19 Truck and in an orthodox orientation, enter the Fort Pitt Tunnel.

The route meets the southern terminus of I-279 here, and I-376/US 22/US 30 head eastward, while US 19 Truck separates from them and joins I-279 on its northward trek.

Northwest of Ingomar Road, US 19 Truck turns west, paralleling and crossing Pine Creek before it terminates (ends) at a partial Y interchange with US 19.

In 1997, construction began on the interchange at the southern portal of the Liberty Tunnel and opened to traffic on November 20, 1999.