On 22 March 1929 a new, straighter, and wider crossing of the River Nene at Wansford – on the boundary between Huntingdonshire and the Soke of Peterborough – was opened by Mrs Wilfred Ashley, wife of the Minister of Transport. With the new bypass and bridge taking over the A1 number from that date, the old Great North Road running through the village and over the 16th-18th stone arched bridge became the A6118.
The route started on the south-eastern edge of the village (in the parish of Sibson-cum-Stibbington at a junction which, after the A1 was made a dual carraigeway connected only to the northbound A1. It first headed west for 240 metres along London Road before coming to a T-junction, where it turned right to join the main village street, Bridge End. The road to the left is the B671, leading to Elton.
The oldest part of Wansford Bridge has a weight limit of three tonnes and is wide enough for only one lane of traffic, and signs at each end request drivers to give way to traffic already on the bridge. On the far side is Wansford proper, and just after passing its parish church, on our left, we come to a staggered crossroads: one of the few instances where traffic on a Class I road is required to give way to that on an unclassified route. The latter was once part of the A47, but that road, too, now bypasses the village.
On the far side we continue north along what is today called Old North Road: further evidence of its earlier role. The buildings become newer on the northern edge of the village, and we soon reach a roundabout junction with the current route of the A47, part of that road's modified dumbbell interchange with the A1. Here our route ends, although prior to the construction of the A47 bypass in the 1960s the A6118 had continued along the remainder of the Old North Road for a further 300 metres to rejoin the A1 directly.
The road appears to have been reclassified to the C340 in 2017.