 At no point in its route does the A605 meet another A-road with a 6-series number.This apparent isolation is the result of it being truncated at its southern end, and the renumbering of the A604 (crossing at Thrapston) to the A14.It used to leave the A6 road at a junction north of Higham Ferrers but this stretch has been renumbered as the A45 road that terminates at the same A14 junction as the A605 now starts from.