There are several neat tunnels which pass under structures built in the city, and tunnels under terrain near the city.
In Pittsburgh
- Under the south end of the Smithfield Street Bridge
- Under Bigelow Boulevard where it intersects Herron Avenue (see here for more info, here for photos of it being built)
- Under the railroad tracks in Station Square to access the Gateway Clipper Fleet boats on the river
- Under the north approach of the Fort Pitt Bridge, in a corner of Point State Park.
- Under Panther Hollow Boulevard connecting to Anderson Playground (see here)
- Under Bigelow Boulevard in Downtown Pittsburgh (this may be closed off as part of the I-579 urban connector cap project)
- Under Reservoir Drive in Highland Park (see here)
- (closed off ) Under both the Parkway East and the "Jail Trail" (Eliza Furnace Trail) connecting Second Avenue to the location a former neighborhood (see here and here for more info, here for a plan to reopen this tunnel as part of a bike/ped connection)
Near Pittsburgh
- Under the embankment of the East Busway and the Pittsburgh Line railroad tracks, by the Edgewood Pennsylvania Railroad Station
- Under the same embankment, at Whitney Street (more info on these two underpasses here)
- Three former railroad tunnels on the Montour Trail - Enlow Tunnel (see also this), National Tunnel, and Greer Tunnel
- Under a road embankment on the Steel Valley Trail section of the Great Allegheny Passage
- Under a McKees Rocks Bridge approach, at Olivia Street
