Chepstow (Welsh: Cas-gwent) is a town in Monmouthshire, Wales, adjoining the border with Gloucestershire, England. It is located on the River Wye, about 2 miles (3.2 km) above its confluence with the River Severn, and adjoining the western end of the Severn Bridge. It is 16 miles (26 km) east of Newport, 28 miles (45 km) east-northeast of Cardiff, 18 miles (29 km) northwest of Bristol and 110 miles (180 km) west of London.
Chepstow Castle, situated on a clifftop above the Wye and its bridge, is often cited as the oldest surviving stone castle in Britain. The castle was established by William FitzOsbern immediately after the Norman conquest, and was extended in later centuries before becoming ruined after the Civil War. A Benedictine priory was also established within the walled town, which was the centre of the Marcher lordship of Striguil. The port of Chepstow became noted in the Middle Ages for its imports of wine, and also became a major centre for the export of timber and bark, from nearby woodland in the Wye valley and Forest of Dean. In the late eighteenth century the town was a focus of early tourism as part of the "Wye Tour", and the tourist industry remains important. Other important industries included shipbuilding – one of the First World War National Shipyards was established in the town – and heavy engineering, including the prefabrication of bridges and, now, wind turbine towers. Chepstow is also well known for its racecourse, which has hosted the Welsh National each year since 1949.
The town had a population of 10,821 according to the 2001 census, increasing to 12,350 at the 2011 census. It is served by the M48 motorway, and its accessibility to the cities of Bristol, Newport and Cardiff means it has a large number of commuters. It is administered as part of Monmouthshire County Council, and is within the Monmouth parliamentary constituency and Wales Assembly constituency. Chepstow is on the western bank of the Wye, while adjoining villages on the eastern bank of the river, Tutshill and Sedbury, are located in England.
The name Chepstow derives from the old English ceap/chepe stowe, meaning market place or trading centre. The word "stow" usually denotes a place of special significance, and the root chep is the same as that in other placenames such as Chipping Sodbury and Cheapside. The name is first recorded in 1307, but may have been used by the English in earlier centuries. However, the name used by the Normans for the castle and lordship was Striguil (in various spellings, such as Estrighoiel), probably from a Welsh word ystraigyl, meaning a bend in the river. The Welsh name Cas-gwent refers to the "castle of Gwent". That placename itself derives from the Roman settlement Venta Silurum or 'Market of the Silures', now named Caerwent, 5 miles (8.0 km) west of Chepstow, which had been the Romano-British commercial centre of south-east Wales.
The oldest site of known habitation at Chepstow is at Thornwell, overlooking the estuaries of the Wye and Severn close to the modern M48 motorway junction, where archaeological investigations in advance of recent housing development revealed continuous human occupation from the Mesolithic period of around 5000 BC until the end of the Roman period, about 400 AD. There are also Iron Age fortified camps in the area, dating from the time of the Silures, at Bulwark, 1 mile (1.6 km) south of the town centre, and at Piercefield and Lancaut, some 1.5 miles (2.4 km) to the north. During the Roman occupation, there was a bridge or causeway across the Wye, about 0.6 miles (0.97 km) upstream of the later town bridge. Chepstow is located at a crossing point directly between the Roman towns at Gloucester (Glevum) and Caerwent (Venta Silurum). Although historians think it likely that there was a small Roman fort in the area, the only evidence found so far has been of Roman material and burials, rather than buildings.
After the Romans left, Chepstow was within the southern part of the Welsh kingdom of Gwent, known as Gwent Is-coed. To the north of the modern town centre, a small church was established dedicated to St. Cynfarch (alternatively Cynmarch, Kynemark or Kingsmark), a disciple of St. Dyfrig. This later became an Augustinian priory on what is now Kingsmark Lane, but no traces of it remain. The town is close to the southern point of Offa's Dyke, which begins on the east bank of the Wye at Sedbury and runs all the way to the Irish Sea in north Wales. This was built in the late 8th century as a boundary between Mercia and the Welsh kingdoms, although some recent research has questioned whether the stretch near Chepstow formed part of the original Dyke. It is possible, though not clearly substantiated, that Chepstow may have superseded Caerwent as a trading centre, and been used by both Saxons and the Welsh. The Lancaut and Beachley peninsulas, opposite Chepstow, were in Welsh rather than Mercian control at that time, although by the time of the Domesday Book Striguil was assessed as part of Gloucestershire.
After the Norman conquest of England, Chepstow was a key location. It was at the lowest bridging point of the River Wye, provided a base from which to advance Norman control into south Wales, and controlled river access to Hereford and the Marches. Chepstow Castle was founded by William fitzOsbern, 1st Earl of Hereford, in 1067, and its Great Tower, often cited as the oldest surviving stone fortification in Britain, dates from that time or shortly afterwards. Its site, with sheer cliffs on one side and a natural valley on the other, afforded an excellent defensive location. A Benedictine priory, now St Mary's Church, was also established nearby. This was the centre of a small religious community, the remains of which are buried under the adjoining car park. Monks, originally from Cormeilles Abbey in Normandy, were there until the Dissolution of the Monasteries.