This article is about the Class III road numbered C6 maintained by DfI Roads. For other roads numbered C6, see C6.
The C6 is a long north-south C road within both County Antrim and County Down. It is a predominantly rural road which starts on the A501 at a crossroads near Stonyford Reservoir. From here the road heads south and almost immediately turns off to the left onto Ballyclough Road. The road is fairly windy on its journey passing west of Lisburn until it crosses the B104, after which the road straightens out somewhat. Ireland's busiest railway line, the Belfast - Dublin line, is crossed as the road passes through Lissue Industrial Estate to reach the A3. The River Lagan which marks the county boundary is crossed just south of the A3 before the road passes over the M1 and then under the A1. Finally, the road reaches its end on the B177 (former A1) in the now bypassed town of Hillsborough.