"Thomastown", an incorporated market and post-town, (formerly a parliamentary borough), and a parish, in the barony of Gowran, county of Kilkenny, and province of Leinster, 21 miles (N.) from Waterford, and 59 (S.S.W.) from Dublin, on the mail coach road to Waterford; containing 3054 inhabitants. This place, situated on the river Nore, and on the southern border of the county, was anciently called Grenan; it took its present name from Thomas Fitz-Anthony Walsh, Seneschal of Leinster, one of the earliest English proprietors in Ireland, who built a castle here, and made the town a free borough. By the Irish it was called Bally-Mac-Andom, signifying "Fitz-Anthony's town;" and from its situation at the head of the navigable channel of the Nore, it became at an early period a place of considerable trade and an important military station; it was surrounded with walls, and most of its buildings were castellated. The present town, in 1831, contained 527 houses, most of which are neatly built. Over the river Nore is a handsome stone bridge of five arches, built in 1792, at each end of which is an ancient square tower, formerly connected with the fortifications by which the town was surrounded. The parish comprises 1719 statute acres, as applotted under the tithe act: the land is of good quality and in a state of profitable cultivation. The principal seats are Dangan Lodge, Coolmore, and Flood Hall. The living is a rectory and vicarage, in the diocese of Ossory, united by act of council in 1803 to the rectories and vicarages of Columbkill and Famagh-Church, and in the patronage of the Bishop. The glebe-house was erected in 1806, and is a neat building about a quarter of a mile from the church; the glebe comprises 18 1/2 acres. In the R. C. divisions the parish is the head of a union or district, comprising also the parishes of Church-Jerpoint, West-Jerpoint, Columbkill, Kilfane, Tullowherin, and Killlarney, in which union are four chapels; the chapel in the town is a handsome edifice with a spire, and contains the great marble altar removed from the ruins of Jerpoint abbey. About 80 children are taught in two public schools, of which the parochial school is supported by the Earl of Carrick, who built the school-house, and by the rector; and there are three private schools, in which are about 230 children, two Sunday schools and a dispensary.
In the vicinity of the town are the remains of Grenan Castle; and on the rover, a little below the town, are those of Dysett Castle, said to have been the birthplace of Rev. George Berkeley, the learned Bishop of Clogher, who was born in 1684. Lagan Castle, near the town, was the residence of the last abot of Jerpoint: there are also some remains of the Dominican abbey.
[From A Topographical Dictionary of Ireland (1837)]