WELSHPOOL (or Welchpool, so called because Pool, its old name, led to confusion with Poole, in Dorsetshire; Welsh Trallwm), a market town and municipal and contributary parliamentary borough of Montgomeryshire, N. Wales, in the upper Severn valley, on the Montgomeryshire canal and the Cambrian railway, 8 m. N. of Montgomery, and 182 m. from London. Pop. (1901) 6121. Its buildings and institutions include the old Gothic church of St Mary, the Powysland Museum, with local fossils and antiquities, and a library, vested (with its science and art school) in the corporation in 1887. Powis Castle (about a mile S.W. of the town) is the seat of Earl Powis, and has been in the possession of the Herberts for many generations. The flannel manufacture has been transferred to Newtown, but Welshpool has tweeds and woollen shawls, besides a fair trade in agricultural produce, malting and tanning. The town returned a member to parliament from 1536 to 1728, was again enfranchised in 1832, and now (with Llanfyllin, Llanidloes, Montgomery, Machynlleth and Newtown) forms the Montgomery district of parliamentary boroughs. A charter was granted to the town by the lords of Powis, confirmed by James I. (1615), and enlarged by Charles II. The castle was begun, in or about 1109, by Cadwgan ab Bleddyn ab Cynfyn (Cynvyn), and finished by Gwenwynwyn; in 1196 it was besieged, undermined and taken by Hubert, archbishop of Canterbury. Retaken by Gwenwynwyn in 1197, it was dismantled by Llewelyn, prince of N. Wales, in 1233. It then remained for several years in the hands of the lords of Powis. During the Civil War, the then lord Powis, a royalist, was imprisoned, and the castle was later demolished. Powis Castle, being of red sandstone, is usually called in Welsh Castell Coch (red castle). In the park is Llyn du (black pool), whence Welshpool is said to be named.