At the beginning of the century the county was dominated by James Butler, 2nd Duke of Ormonde, the grandson and heir of the 1st Duke. Not only did he possess huge estates, but he also controlled the Palatinate of Tipperary. He was indisputably the greatest nobleman and landowner in Ireland. He was Lord Lieutenant from 1703 to 1707 and again from 1710 to 1713. Ormonde was a strong Tory, and in 1714 he backed the wrong side. Threatened with impeachment, he fled to France and was subsequently attainted, his estates confiscated and the Palatinate abolished. Ormonde had a surviving brother and the head of the Butler family was now Charles Butler, Earl of Arran, who managed to buy back part of the family estate after his brother's attainder.
In 1758 Arran died childless and the head of the family was John Butler of Kilcash, a great-great-nephew of the 1st Duke, the great-grandson of his brother Walter. John Butler also left no son and was succeeded by his cousin Walter Butler, who died in 1783 and was succeeded by his son John Butler (0322), then MP for Kilkenny city and previously MP for Gowran. John Butler's parents were both Catholic but he had conformed and married Lord Wandesford's only child, a great Kilkenny heiress. John Butler also queried the 2nd Duke's attainder as it applied to all his titles. The dukedom and the marquessate were extinguished with the line of the 1st Duke but the earldom was older and, as a descendant of the 11th Earl, John Butler successfully claimed it and took his seat in the Irish House of Lords in 1791 as 17th Earl of Ormonde.208 During the last quarter of the century the Butlers gradually returned to their position as the dominant force in Kilkenny politics.
In the middle of the century two Cromwellian families, the Ponsonbys and the Agars, emerged to fill the vacuum, as did other less prominent interests such as the Floods. In 1785 the county was 'said to be governed by the aristocratic interest. Lord Bessborough (1707) and Mr Ponsonby (1702), Lord Clifden (0016), Mr Butler (0325), and Mr Flood (0762) and Mr Agar (0013) have the chief interests. Whilst Mr Ponsonby and Lord Clifden continue united they can manage the County.' The Ponsonby rise owes much to the astuteness of Brabazon Ponsonby, firstly in his own first marriage to Sarah Colvill (née Margetson), from whom he acquired the only piece of borough property that the Ponsonbys possessed, the borough of Newtown(ards), Co. Down; secondly through the marriages of his two sons to two daughters of the 3rd Duke of Devonshire; and thirdly in acquiring for himself and his younger son the office of First Commissioner of the Revenue with all the patronage that went with it. In 1790 it was said that 'The Ponsonby interest in the county is all powerful, partly from personal attachment, but much more from extensive property and a continued attention to making Freeholders.'
One of the county MPs was the popular W. B. Ponsonby, and 'Mr Walter Butler, eldest son of the head of the Butler family and representative of the honoured house of Ormonde is the other member for the county unanimously elected on Lord Clifden's (0013) succession to his father's title the name of Butler was long the irradiating luminary in this county and though since its descent from the zenith little stars have arisen into distinction, we cannot conceive that their united influence will be able to obscure its lustre.'209The electorate was small, estimated at 1,052 votes in 1784, and even after Catholic enfranchisement in 1793 it was only about 2,300 in 1815. By joining together, the Butlers and the Ponsonbys avoided a general election in the period after the Union.
Co. Kilkenny had six boroughs - Callan, Gowran, Innistiogue, Knocktopher, St Canice/Irishtown and Thomastown - besides the county borough of Kilkenny city.