Armstrong Tunnel

The Armstrong Tunnel in Pittsburgh, Pennsylvania, connects Second Avenue at the South Tenth Street Bridge, under the Bluff where Duquesne University is located, to Forbes Avenue between Boyd Street and Chatham Square.

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Tunnel data from Wikidata (CC0). Summary from Wikipedia (CC BY-SA).

Other tunnels in United States

Delaware Aqueduct United States · 137 km Päijänne Water Tunnel Finland · 120 km Orange–Fish River Tunnel South Africa · 82.8 km Ishikawa Tunnel Japan · 78.5 km Brenner Base Tunnel Austria · 64 km Mont d'Ambin base tunnel France · 57.5 km Gotthard Base Tunnel Switzerland · 57.09 km Hong Kong–Zhuhai–Macau Bridge China · 55 km