Blisworth Tunnel has no tow path inside, but is wide enough for two narrowboats to pass in opposite directions. Work began in 1793, but errors by contractor left a wiggle in the tunnel, and after three years work it collapsed due to quicksand, claiming the lives of 14 men. It was then decided to begin again with a new tunnel. By the time the rest of the Grand Junction Canal had opened between London and Braunston, Northamptonshire in 1800, apart from the crossing of the River Great Ouse, the section of canal from Blisworth to the lower end of Stoke Bruerne locks
Union Canal (Pennsylvania) closure in 1881. In April 1950, the Union Canal Tunnel was purchased by the Lebanon County Historical Society. The tunnel was placed on the National Register of Historic Places on October 1, 1974. It was designated a National Historic Civil Engineering Landmark in 1970. On April 19, 1994, the tunnel was designated a National Historic Landmark by the Secretary of the Interior Bruce Babbitt. The tunnel is open to visitors in the Union Canal Tunnel Park. A restored portion of the canal along Tulpehocken Creek is maintained by the Berks County Parks System at the Union Canal Towpath Park in