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
Northamptonshire the M1 motorway, the A43 between Northampton and the county boundary near Stamford, the A361 between Kilsby and Banbury (Oxon) and all B, C and Unclassified Roads. Since 2009 these highways have been managed on behalf of the county council by MGWSP, a joint venture between May Gurney and WSP. Two major canals – the Oxford and the Grand Union – join in the county at Braunston. Notable features include a flight of 17 locks on the Grand Union at Rothersthorpe, the canal museum at Stoke Bruerne, and a tunnel at Blisworth which, at , is the third-longest navigable canal