MONTGOMERYSHIRE (Welsh Swydd Tre’ Faldwyn, Baldwyn’s town shire), a county of Wales, bounded N. by Denbigh, N.E. and E. by Shropshire, S. by Radnor and Cardigan, W. and N.W. by Merioneth. Its length from S.E. to N.W. is about 30 m.; N.E. to S.W. it measures about 35 m. The surface is broken, though the highest hills are only round the county borders—to the north Berwyn (stretching into Denbighshire); to the south-west Plinlimmon (q.v.); east, the Breidden hills; south, the Kerry hills. The principal rivers and streams are: the Severn, flowing east and north; the Wye, farther south; the Dyfi, Vyrnwy (Fyrnwy), Clywedog, Tanat and Rhiw. Except the Wye and Dyfi, the principal streams are tributaries of the Severn. Lake Vyrnwy, formed in 1888, is the chief water-supply of Liverpool. The Montgomeryshire canal, some 24 m. long, is connected with the Shropshire Union and Ellesmere canals, The county was formerly a recognized source of oak timber for the navy.
Geologically, the county is occupied almost exclusively by Ordovician and Silurian rocks. The latter, mainly Wenlock beds bordered by a fringe of Llandovery rocks, lie in the form of a complex syncline down the centre of the county from a few miles north of Lake Vyrnwy through Llangadfan, Llanfyllin, Llanfair, Welshpool, Montgomery and Newtown. The boundary is very irregular. Between Newtown and Kerry hill Ludlow beds come in, and on the edge of the forest of Clun the Old Red Sandstone just crosses the boundary into this county. North and south of the Silurian tract the Ordovician rocks occupy the remaining area; they contain bands of andesite and felsite in the Berwyn hills, also east of Criggion and south-west of Corndon. In the last-named hill there is a large laccolitic mass of dolerite and a similar rock occurs at Criggion. At Machynlleth slate is worked in the Ordovician, and numerous metalliferous mines exist in the neighbourhood of Newtown from which lead, silver and zinc are obtained. Glacial deposits are prevalent over much of the county.
The climate is mild, and the soil generally fertile, especially in the Severn valley, though towards Merionethshire there are heath and moss. Small holdings (under about 50 acres) tend to diminish. The hardy, small, mountain pony is still to be found here. Hunters and cart-horses are bred. Sheep-breeding is practised, and Shropshire downs are superseding the little cluns. Of the relatively few green crops potatoes are the most important; oats are the principal grain. Permanent pasture covers a large area. Hill pasture is also extensive. Woollen cloth and flannel manufacture have revived considerably.
The Cambrian railway, entering Montgomeryshire in the north-east, by Llanymynech, crosses it to the south-west with branches to Llanfyllin, Westbury and Van. There is also a branch from Caersws to Glandyfi (Glandovey) junction, with the coastwise branch of the same company.
The area of the ancient and administrative counties is 510,111 acres, or 797 sq. m., with a population of 54,901 in 1901. Many of the people know no English, and Welsh is everywhere the favourite speech. The county returns one member to parliament, and includes the Montgomery district of parliamentary boroughs: Llanfyllin (pop. 1632), Llanidloes (2770), Montgomery (1034), Machynlleth, Newtown and Welshpool (6121). The first three and last of these are municipal boroughs. The urban districts are: Newtown and Llanllwchaiarn (6500), and Machynlleth (2038). The county is in the North Wales and Chester circuit, assizes being held alternately at Newtown and Welshpool. Welshpool borough has a separate commission of the peace, but no separate court of quarter sessions. The ancient county (in Bangor, Hereford, and St Asaph dioceses) has 59 ecclesiastical parishes or districts, with parts of 11 others.
History and Antiquities:—The Welsh name of Baldwyn’s town shire is taken from a Norman who did homage to William the Conqueror for this division of Wales. The English name is from Roger de Montgomery, earl of Shrewsbury (temp. William Rufus). At the coming of the Romans this county was part of the Ordovices' territory (Britannia secunda), and there are remains of Roman encampments and fortifications at Caersws, Mathrafal, and near Montgomery. The roads connecting these stations can often be traced. Vestiges of a Roman camp are visible near Welshpool. Machynlleth was perhaps the Roman Maglona. Remains of old British camps are to be seen at Dolarddyn, on Breidden hill and at Caereinion. There are many cairns and barrows. Crossing the county was the Via Devana, joined by other roads. From the Roman evacuation under Flavius Honorius (d. A.D. 423) little is known of Montgomery until Wales was subdivided into three districts at the death of Rhodri Fawr, when Montgomery was included in Powys (Powys Gwenwynwyn, Upper Powys). Powys Castle was founded in 1108. About the end of the 11th century, probably, was built Baldwyn’s Castle, taken later by the Welsh and retaken by Roger de Montgomery. In 1345 Roger Mortimer held it. At Carno, 11 m. from Newtown and 17 from Machynlleth, a battle decisive of North Wales sovereignty was fought in 946, and in 1081 the rightful heir, Gruffydd ab Cynan, together with Rhys ab Tudur, prince of South Wales, here killed in battle Trahaern ab Caradoc, the usurper, and most of his men. At Machynlleth is seen Owen Glendower’s senate house (1402) where he was crowned prince of Wales.