The A37 is a major road in south west England. It runs north from the A35 at Dorchester in Dorset into Somerset through Yeovil and Shepton Mallet before terminating at the Three Lamps junction with the A4 in central Bristol. The road is entirely single carriageway, except in the Yeovil and Bristol built-up areas, at Ilchester (where it multiplexes with the A303), and north of Dorchester.