"Johnstown", a post-town, in the parish of Fartagh, barony of Galmoy, county of Kilkenny, and province of Leinster, 13 miles (W.N.W.) from Durrow, and 58 (S.W.) from Dublin, on the road to Cork, by way of Cashel; containing 146 houses and 875 inhabitants. It is the property of Gorges Hely, Esq., whose seat, Violet Hill, is in the immediate vicinity; and contains a neat church, a commodious R.C. chapel, and a dispensary. Fairs are held on Jan. 3rd, March 2nd, April 18th, May 18th, June 25th, Aug. 11th, Oct. 27th, and Dec. 19th, chiefly for pigs. It is a chief constabulary police station, and has petty sessions every fortnight and a manor court monthly. Gold coins have been found here of the reigns of Henry, Elizabeth, Jas. II, and Wm. III. In the vicinity is the much frequented spa of Ballyspellin, which has been the subject of some humorous lines by Drs. Sheridan and Swift. The spa is formed by the filtration of water through limestone, after which it is passed through ferruginous slate, and contains carbonic acid gas, iron, and possibly fossil alkali. Several treatises have been written on its medicinal properties, and it is stated to be of great efficacy in obstructions, relaxations, and recent dropsies. Coal is supposed to exist in the hill from which it flows.
[From A Topographical Dictionary of Ireland (1837)]