Grand Junction Canal Nene at Northampton, to the turnpike road at Old Stratford (north-west of the modern Milton Keynes), and to Watford in Hertfordshire: those to Daventry and Watford were not built. The branch to Old Stratford was amended before it was built (see below). The branch to Northampton was delayed as the plans of the Leicestershire and Northamptonshire Union Canal to reach Northampton and thus join with the Grand Junction came to nothing. The link to Northampton was made by a tramroad transferred from Blisworth Tunnel, with the 5-mile (8-kilometre) canal from Gayton being opened in 1815. The link to Leicester was
Blisworth centuries iron ore and limestone were quarried at Blisworth. A limestone quarry began in 1821 north east of the canal tunnel and was connected to a canal wharf at the west end of the tunnel by horse-drawn tramway. The tramway ran from the quarry, across the Stoke Bruerne Road and above the west end of the tunnel. Trains of loaded wagons descended by gravity and empty ones were pulled up by a horse. There was a chute for filling the canal boats from the stone wagons .The quarry was closed in 1912 or 1913. A trial iron ore quarry operated