Monmouthshire, a western border county of England, bounded E. by Gloucestershire, N. E. by Herefordshire, N.W. by Brecknock, W. and S.W. by Glamorganshire (Wales), and S. by the estuary of the river Severn. The area is 534 sq. m. The surface is varied, and in many districts picturesque, especially along the valley of the Wye, and between that river and the Usk. In the west and north the hills rise to a considerable height, and this mountain region encircles a finely undulating country. The highest summits are Sugar Loaf (1955 ft.), Blorenge (1838), and Skirrid Fawr (1601), summits of the hills which almost encircle the town of Abergavenny. On the other hand, along the shore of the Severn estuary on either side of the Usk, are two extensive tracts of marshland, called the Caldicot and Wentlloog levels, stretching from Cardiff to Portskewet, and protected from inundations by strong embankments. The principal rivers are the Wye, which forms the greater part of the eastern boundary of the county with Gloucestershire, and falls into the Severn; the Monnow, which forms a portion of its boundary with Herefordshire, and falls into the Wye at the town of Monmouth; the Usk, which rises in Brecknock, and flows southward through the centre of the county; the Ebbw, which rises in the north-west, and enters the estuary of the Usk below Newport; and the Rhymney, which rises in Brecknock, and, after forming the boundary between Monmouth and Glamorgan, enters the Bristol Channel a little east of Cardiff. Salmon abound especially in the Wye and the Usk, and trout are plentiful in many of the streams.
The oldest rocks in the county are the Silurian strata (Wenlock Shale and Limestone, and Ludlow Beds) which form an extensive anticline at Usk; a smaller inlier appears at Rumney on the south-west borders of the county near Cardiff. These beds dip under the Old Red Sandstone, a great series of red marls, sandstones and concretionary limestones (cornstones) which occupies the north-eastern part of the county; the highest beds contain grits and conglomerates which give rise to bold escarpments and lofty plateaux (e.g. the Sugar Loaf and Skirrid Fawr) alongside the outcrop of the Carboniferous Limestone. The western part of the county, between Pontypool and the river Rhymney, is occupied by the eastern end of the great South Wales coal-field, where the Carboniferous Limestone, Millstone Grit and Coal Measures (Lower Coal Series, Pennant Sandstone and Upper Coal Series) dip westward and succeed each other from east to west. The Coal Measures abound in coal-seams and ironstone, and their densely populated valleys offer a marked contrast to the agricultural and pastoral districts of the rest of the county. The Carboniferous Limestone comes in again in the south-east near Chepstow, and has imparted its characteristic scenery to the lower reaches of the Wye. After a prolonged interval, during which these older formations were folded, faulted, upheaved and finally carved by erosion into hills and valleys, the southern portion of the region was submerged beneath the waters of the Triassic lake in which the Keuper Marls were deposited. These consist of red conglomerates and marls which wrap round the heights and fill up the hollows among the older rocks to the south-west of Chepstow, and the subsidence continuing, admitted the waters of the Jurassic sea which deposited the fossiliferous Rhaetic and Lias limestones and shales of Llanwern and Goldcliff near Newport. Glacial gravel and boulder-clay are found in the valleys and a broad tract of alluvium borders the shores of the Bristol Channel.
Along the Severn shore the soil is deep and loamy, and admirably suited for the growth of trees. The most fertile land is that resting on the Red Sandstone, especially along the banks of the Usk, where wheat of fine quality is raised. In the mountainous regions more attention is paid to grazing than to the raising of crops. There are a considerable number of dairy farms, but sheep-farming is much more largely followed. Only about seven-tenths of the total area of the county is under cultivation. There is a large extent of hill pasture, and a considerable acreage under orchards.
The coal-mines and iron-works which Monmouthshire shares with South Wales are very important. They occur in the wild and mountainous western part of the county, where a series of upland valleys, running parallel from N.N.W. to S., has each its populous mining townships and railways, which have in many cases necessitated remarkable engineering works - such as the great Crumlin viaduct. These valleys, in order from east to west, with the principal townships in each, are as follows: Afon Lwyd (Panteg, Pontypool, Abersychan and Blaenavon); Ebbw Fach (Abertillery, Nantyglo and Blaina), joining the Ebbw (Risca, Ebbw Vale); Sirhowy (Bedwellty and Tredegar); Rhymney (New Tredegar and Rhymney). Besides coal, a considerable quantity of fire-clay and some iron are raised.
The principal railway serving the county is the Great Western, but in the mining districts there are also various branches of the London and North-Western, Rhymney and Brecon and Merthyr systems. The Crumlin Canal from the Ebbw Valley, and the Monmouthshire Canal from Pontypool converge upon Newport, which is the principal port in the county. The Brecon Canal runs north from Pontypool into the valley of the Usk.
The area of the ancient county is 341,688 acres, with a population in 1891 of 252,416, and in 1901 of 292,317. The area of the administrative county is 349,712 acres. The county comprises 6 hundreds. The municipal boroughs are Abergavenny (pop. 7795), Monmouth (5095), and Newport, a county borough (67,270). The following are urban districts: Abercarn (12,607), Abersychan (17,768), Abertillery (21,945), Bedwellty (9988), Blaenavon (10,869), Caerleon (1367), Chepstow (3067), Ebbw Vale (20,994), Llanfrechfa, Upper (2979), Llantarnam (5287), Mynyddislwyn (3337), Nantyglo and Blaina (13,489), Panteg (7484), Pontypool (6126), Rhymney (7915), Risca (9661), Tredegar (18,497), and Usk (1476). Monmouthshire is in the Oxford circuit, and assizes are held at Monmouth. It has one court of quarter sessions, and is divided into II petty sessional divisions. The boroughs of Monmouth and Newport have commissions of the peace, but no separate court of quarter sessions. The parliamentary divisions are the northern, western and southern, each returning one member; and the Monmouth district of parliamentary boroughs, consisting of the towns of Monmouth, Newport and Usk, returns one member.
The district which is now Monmouthshire formed the Welsh kingdom of Gwent at the time of the Heptarchy, and, owing to the extraordinary courage of the Gwentians in resisting the repeated inroads of the Saxons, no permanent English settlement was effected in the district until close upon the middle of the 11th century. The incursions of the West Saxons began in the 7th century, and, during the reign of Alfred, Brochmael and Fermael, kings of Gwent, acknowledged Alfred as their lord, and sought his protection against their enemies. In the 9th and 10th centuries the district was frequently harried by the Danes, who in 915, under Ohter and Hwald, sailed round Wessex and Cornwall to the mouth of the Severn and plundered all along the banks of the Wye, finally taking prisoner the bishop of Llandaff, whom they only released on a ransom of £40. In 926 Æthelstan obliged the kings of the north Britons to meet him at Hereford and fixed the Wye as the limit of their territory. In 976 the Danes destroyed Caerleon, at this time the chief town of the district. The early 11th century was taken up with a series of interminable contests between the Welsh princes for the succession in South Wales, as a result of which the Welsh Chronicle relates that in 1047 the whole of South Wales lay waste, and in 1049, when a fleet of Irish pirates entered the Severn estuary, Griffith, the king of South Wales, assisted them in plundering the neighbourhood. In 1065 Harold conquered the whole district between the lower reaches of the Wye and the Usk, and gave orders for the construction of a hunting-box at Portskewet for Edward the Confessor, but very shortly after Caradoc ap Griffith, with a large body of followers, killed all the workmen engaged in the building and carried away the provisions prepared for the king's reception.
After the Conquest the district conquered by Harold was bestowed on William Fitz Osborne, earl of Hereford, who built Monmouth Castle, and continued the line of defence against the Welsh frontier along the Wye, while a second line of fortifications along the Usk Valley marked the continued advance of the Normans, who by 1085 had subjugated almost the whole of Gwent. The lordship of Overwent fell to Hamelin de Baladun, who founded the castle and priory of Abergavenny, and from him passed to Brian Fitz Count and later to Walter Fitz Miles, earl of Hereford. The lordship of Netherwent remained for many centuries with the Clare family. Penhow Castle was a stronghold of the family of St Maur or Seymour, from whom are descended the present dukes of Somerset, and Grosmont and Skenfrith Castles of the family of Braose. Gwent still ranked as Welsh territory at the time of the Domesday Survey, but the town of Monmouth, the castle of Caerleon, and the district of Archenfeld, are assessed under Herefordshire, and the three hardwicks of Llanwern, Portskewet and Dinam under Gloucestershire. The Norman lords of the present county held their lands "per baroniam," so that the king's writ did not run in them, and the lives and property of the poorer inhabitants were entirely at the mercy of these lords marchers as they were termed. The county still exhibits remains of no less than twenty-five Norman castles. The province of Gwent was formerly divided into four cantrefs, each comprising several commotes. Cantref Uwchcoed, or Upper Gwent, comprised the commotes of Erging and Ewyas, now principally in Herefordshire, and the greater part of the present hundreds of Skenfrith, Abergavenny and Usk; Cantref Iscoed, or Lower or Nether Gwent, comprised the present hundred of Raglan and parts of Caldecote and Usk; Cantref Gwentlwg comprised the present hundred of Wentlwg; while the fourth cantref, Cantref Coch, now forms the Forest of Dean in Gloucestershire. Leland, writing in the 16th century, describes Gwent as comprising the three divisions of low, middle and high "Venteland," and at this period it included no less than 24 lordship marches, each governed by its own ancient laws and customs and ruled by its own lord. Under the act of 1536 for the abolition of the marches, these 24 lordships were united to form a shire; Monmouth was constituted the shire town, and the sheriff's court was ordered to be held alternately at Monmouth and Newport. A commission was also appointed to divide the shire into hundreds, which were made 6 in number: Abergavenny, Caldecote, Raglan, Skenfrith, Usk and Wentlwg, the bounds being subsequently ratified by act of parliament of 1542-1543. No sheriffs were actually appointed for Monmouthshire until 1541, and the legal authority of the lords marchers was not finally abolished until 1689. The act of 1536 did not expressly separate the county from Wales, and it was only gradually that Monmouthshire came to be regarded as an English county, being included in the Oxford circuit for the first time in the reign of Charles II.
Ecclesiastically Monmouthshire has been almost entirely included in the diocese of Llandaff since the foundation of that diocese in the 6th century. Monmouth, however, was in the diocese of Hereford, and a few parishes formed part of the diocese of St Davids, until under the statute of 1836 the whole county was placed under the jurisdiction of the bishop of Llandaff. It contains, wholly or in part, 134 ecclesiastical parishes.
The river fisheries of Monmouthshire have been famed from very early times, Caerleon with seven fisheries in the Wye and the Usk yielding a return of 7, ros. at the time of the Domesday Survey. Coal is said to have been worked in the reign of Edward I., but the industry lapsed altogether until it received new life from the construction of the canal between Blaenavon and Newport, begun in 1792 and completed in 1795. The first iron-workers at Pontypool were a family of the name of Grant, who were succeeded in 1565 by Mr Richard Hanbury. In 1740, however, Monmouthshire contained only two furnaces, making 900 tons annually. Fifty years later three new furnaces were constructed at Blaenavon, and from that date the industry steadily improved.
By the act of 1536 two knights were to be returned for the shire and one burgess for the borough of Monmouth, but the first returns for the county were made in 1547 and for the borough in 1553.
From 1698 the boroughs of Newport and Usk returned one member each. Under the Redistribution of Seats Act of 1885 the county now returns three members in three divisions.
Of Norman fortresses in Monmouthshire, either built or taken possession of by the lords of the marches, there are remains of no less than twenty-five. The more interesting and important are: Caldicot, the seat of the De Bohuns, with a round keep of the 13th century, gatehouse and other portions, still partly inhabited; Chepstow, one of the finest examples of the Norman fortress extant, in an imposing situation on a cliff above the Wye; Newport, Abergavenny, the gateway and hall of Grosmont, once the residence of the dukes of Lancaster; and Usk Castle, rebuilt by the Clares in the time of Edward IV. Raglan Castle, begun in the reign of Henry V., is a very extensive ruin, still in good preservation, and of special interest as a very late example of the feudal stronghold. Charles I. resided in it after the battle of Naseby, and in 1646 it was delivered up to the parliamentary forces after a stubborn resistance of ten weeks against Colonel Morgan and General Fairfax.
At the Reformation there were in Monmouth two hospitals and fifteen other religious houses; but of these there are now important remains of only two - Llanthony Abbey and Tintern Abbey, both Cistercian. Llanthony Abbey in the Black Mountains was founded by William de Lacy in 1103, and the church, dating from about 1200, is one of the earliest examples in England of the Pointed style. The ruins consist of portions of the nave, transept, central tower and choir. Tintern Abbey (q.v.), founded by Walter de Clare in 1131, occupies a position of great beauty on the Wye, and is among the finest monastic ruins in England. Of the churches, those chiefly worthy of mention are at Abergavenny, belonging to a Benedictine priory, and containing a number of old tombs; Chepstow, partly Norman, and possessing a richly moulded doorway; St Woolos' Church, Newport, also Norman; the Norman chapel of St Thomas, Monmouth; Christchurch, principally Norman; Mathern, Early English, with a tablet to Tewdrig, king of Gwent in the 6th century; and Usk, formerly attached to a Benedictine priory.
See Victoria County History, Monmouthshire; William Coxe, An Historical Tour in Monmouthshire, 2 pts. (London, 1801); N. Rogers, Memoirs on Monmouthshire (London, 1708); David Williams, History of Monmouthshire (1796); George Ormerod, Strigulensia. Archaeological Memoirs relating to the District adjacent to the Confluence of the Severn and the Wye; M. E. Bagnall-Oakeley, Account of the Rude Monuments in Monmouthshire (Newport, 1889); J. A. Bradney, A History of Monmouthshire (1904, &c.); also the publications of the Caerleon Antiquarian Association.