 The road split in two just before the A6 with one branch joining the A6 by the Irthlingborough Viaduct and the other at the top of the hill as the A6 enters Higham Ferrers.The later branch survives as a local access but the former has been returned to field.In the early 1980s, development of the route from Northampton to Thrapston saw the building of a new section of the A605 mostly on line between Chown's Mill roundabout and the Stanwick roundabout.