Washington Street Tunnel (Chicago)

The Washington Street Tunnel was a tunnel that ran beneath the Chicago River in Chicago, Illinois, carrying vehicular traffic. Constructed between 1867 and 1869, it connected the north and south sections of Washington Street.

Its construction was necessitated by the heavy river traffic that frequently interrupted street traffic via swing bridges. The tunnel allowed for continuous east-west passage under the river, particularly important for commerce and emergency services.

The tunnel was built using a method involving sinking iron tubes into the riverbed and then excavating the earth within them. It was illuminated by gas lights.

As Chicago's population and transportation needs grew, the Washington Street Tunnel became increasingly inadequate for the volume of traffic. Furthermore, its steep approaches proved problematic for some vehicles, especially horse-drawn carriages and early automobiles.

The Washington Street Tunnel was closed to vehicular traffic in 1956. The tunnel was later filled in, with the approaches to the former tunnel removed and the street surface restored. Today, no visible trace of the tunnel remains above ground.