Taghmon was a borough by prescription; no charter could be found for it in 1800. It is mentioned in 1642, so it must have existed before then. It conformed to the usual pattern of a sovereign and 12 burgesses. The town was:
much declined from that degree of consequence which, in early days, it seems to have possessed now a very paltry village, eminent for nothing but its saleable representation. Reduced to a close Borough, its electors are confined to the twelve Burgesses, who are always chosen agreeably to the pleasure of Mr Hore (1037), of Harperstown who is absolute master of the Corporation and the nominator of its Members in the House of Commons.
In 1783 it had '13 burgesses, few resident, few inhabitants, Patron Mr Hoare'. The Hores, who were related to the Grogans, appear to have controlled the borough throughout the century. William Hore (1038) sat for the county from 1709 to 1713, and three members of the family (1036, 1037, 1039) sat for Taghmon 1727-68. Among their famous purchasers were the Hely-Hutchinsons, and in 1797 Lord Donoughmore told Lord Sudley that the seat for his father, John Hely-Hutchinson (1001), had been secured by paying £1,400 two years before it was due to become vacant and a further £200 at the time of the vacancy: poverty perhaps explains why they consistently sold the seats in the later eighteenth century and finally sold the borough itself to Henry Bruen (0268) in the early 1790s. The £15,000 for its disfranchisement was paid to the Trustees of the estate of Henry Bruen, who died in 1795.