This article is about the Class III road numbered C646 maintained by DfI Roads. For other roads numbered C646, see C646.
The C646 is a medium length C class route starting on the B130 at Curran. The road heads north west and crosses the B45 at two separate junctions in the small village of Eglish. Beyond the village, a spur heads westwards to reach the B35, keeping north of Oona Water. The main line of the route crosses the B35 at a crossroads at crosses the A4 at a pair of roundabouts with both carriageways being accessible via two separate LILO junctions. Soon the road comes to an end on the C684 (former A4) to the south of Castlecaulfield.