 The A686 begins at a roundabout with the A66 road and A6 road on the edge of Penrith, Cumbria, though it originally started in nearby Carleton at a crossroads with the former route of the A66.The road heads in a north-easterly direction crossing the River Eden before going through the village of Langwathby.It continues through Melmerby and across the Pennines before reaching the isolated market town of Alston.