The B671 is a short B-road in northern Huntingdonshire. It starts on the A605 to the south of Elton and heads north into the village along what is the pre-bypass line of the A605. There is a TOTSO left in the centre of Elton marking what was formerly southern end of the B671; the unclassified road ahead is the original line of the A605 into Peterborough.
The B671 continues north, running parallel to the River Nene (which remains invisible) to th,e west. There are few buildings on this road, but after a mile or so the road passes Sibson Aerodrome (a.k.a. Peterborough/Sibson Airport). The road then passes a line of houses on the edge of Stibbington before entering Wansford. Here the B671 ends just to the south of the Nene Bridge on the A6118 (former A1) – at the point where that road, having crossed the old bridge, turns to join the present route of the A1.