The M48 is a 13-mile (21 km) long motorway in Great Britain, which crosses the Severn near Chepstow, Monmouthshire, linking England with Wales via the Severn Bridge. This road used to be the M4, and as a result is anomalously numbered: as it lies to the north of the M4 and to the west of the M5, it is in the Motorway Zone 5. The M4, M48 and the A48(M) motorway are the only motorways in Wales.[citation needed] From Wikipedia