This article is about the Class III road numbered C278 maintained by DfI Roads.
For other roads numbered C278, see C278
The C278 starts on the A7 in Crossgar at a mini roundabout opposite the B7. The road heads in a southward direction out into the countryside where it TOTSOs across Ballynahinch River into the small village of Kilmore. After passing through the village, the road TOTSOs again to the south and soon crosses the B2 at Annacloy. From here the road continues south west, gradually swinging west as it crosses the route of the C288 at a crossroads near Loughinisland Lake. Upon reaching Loughinisland itself, the road comes to a T junction and turns to the south. Just before reaching the A24, the road turns north at another T junction and after a very short distance ends on the A24.