This article is about the Class III road numbered C509 maintained by DfI Roads.
For other roads numbered C509, see C509
The C509 commences from a T junction marking the end of the B44 in the village of Park and immediately crosses the River Faughan. The road heads west before abruptly swinging round to the north as it passes its junctions with the C511 and the C512. The road works its way along lower slopes of Slieveboy and soon meets the C513 at a crossroads. The road continues north west before sharply turning west to terminate on the B49 just outside Claudy.