Pennsylvania Canal Tunnel

The Pennsylvania Canal Tunnel was the Pittsburgh terminus of the Pennsylvania Main Line of Public Works, a transportation system that involved other early tunnels. Construction was authorized February 8, 1827,[3] and the tunnel was completed November 10, 1829.[1] The canal crossed the Allegheny River on a covered bridge aqueduct, later replaced by John A. Roebling's first suspension bridge, the Allegheny Aqueduct.,[4] the canal traveled underground through most of downtown Pittsburgh, under Grant's Hill, to end in a lock leading to the Monongahela River.[5][6] The original plan was to connect with the C&O canal at the Monongahela River, but that canal never reached its expected western end, and the tunnel's main use was to allow overflow from the canal to enter the Monongahela.[7] Only one or two canal boats ever went through the tunnel and lock.[8] The tunnel was made obsolete by the arrival of the Pennsylvania Railroad in 1852.

The canal tunnel was uncovered during the construction of the U.S. Steel Tower in 1967,[1] and later during the construction of the subway system, which used part of the tunnel on the south side.