It starts on the A71 by the church in Drumclog. The road narrows immediately and heads south through the village. It runs through an old railway embankment (where the actual bridge has been removed) before crossing a stream. The road continues south across flat terrain before turning sharp left at a crossroads to cross the Glengavel Water.
The road now heads east-north-east for a couple of hundred metres before bearing right to start climbing out of the shallow valley. It ends soon afterwards at a T-junction with the B743 (former B744) opposite Dungavel House, now an immigrant detention centre.