The route of the main new trunk road is a route at Blisworth and Milton Malsor in the County of Northamptonshire approximately 6.62 kilometres in length, starting at a point 290 metres north-east of the junction of the existing (A43) trunk road with St John’s Road then going in a generally northerly direction to a point on Banbury Lane, 590 metres south of its junction with the Danes Camp Way/Upton Way Roundabout.