It is some 30 kilometres across the rhomboid as the crow flies from the town of Sanquhar just to the west of the Lowthers to the towns of Beattock and Moffat on the east and some 28 kilometres from the town of Thornhill near the southern apex to Abington near the northern one. Sanquhar and Thornhill lie on the River Nith, Moffat on the River Annan and Abington on the River Clyde. Annandale and Clydesdale taken together, form a corridor between the Lowther Hills and the Moffat Hills (which lie to the east.). This corridor between the hills carries the main route running northwards into Scotland on its west side. It carries both the west coast railway line and the M74 motorway and has been the main route north over centuries. Nithsdale to the west of the Lowthers carries both the A76 road and the rail line from Dumfries to Kilmarnock. The next range of hills to the west beyond the River Nith is the Carsphairn and Scaur Hills.