The B4570 runs inland from Cardigan, following a longer and hillier route than the parallel A484. The road was originally unclassified but gained its number in 1935.
Starting on the A484 to the east of Cardigan the B4570 heads east and soon reaches Llangoedmor, passing to the north of the village centre. A valley, with a narrow bridge over the stream, is crossed, then the road bends sharply right to lessen the gradient as it climbs onto the hill to the east. We pass to the north of another hill before descending into Ponthirwaun.
Continuing southeastwards the road crosses a spur and goes through Capel Tygwydd. A final descent takes us over a narrow bridge into Cwm-cou, where the road ends at a T-junction on the B4333.