This article is about the Class III road numbered C20 maintained by DfI Roads.
For other roads numbered C20, see C20
The C20 actually consists of three separate roads. The first section of the road starts on the B12 in Glenavy and follows the old alignment of the A26 to reach the new A26 just outside the village. The second section starts in Crumlin on a shared junction with the A52 and the B12. From here the road follows the rest of Main Street beyond the end of the B12 and turns onto Ballytromery Road to meet the A26 to the south east. A short distance along the A26, the third section of the C20 turns off to the east with an additional spur linking back to the A26. The road soon reaches its end on the B101 near Dundrod.