Dungarvan was the largest and least easily controlled of the Co. Waterford boroughs. It was originally a Boyle borough, but as early as 1713 it required more attention than it was receiving, as 'Cary of Wexford has half the town'.393 Its first charter was one of 1609/10, 7 James I; originally it was to be a free borough with a sovereign, 12 brethren and free burgesses, but the right of election passed to the freeholders and householders of the Manor of Dungarvan. In the seventeenth century the Manor of Dungarvan was granted to Sir George Thornton and from him it passed to the Earl of Cork, and then in the mid-eighteenth century to the Duke of Devonshire.
The electorate was large, and in the period 1703-97 there were at least nine controverted elections. In 1703 William Hubert and Robert Carew unsuccessfully challenged the election of James Barry (0091) and Roger Power (1719). The sub-committee of the Committee on Privileges and Elections before which the petition came was presided over by Sir Richard Levinge (1230), who reported to the House that a militia troop had been brought from outside the borough to vote. The High Sheriff, Mr Carew, antedated the precept for the election to 30 August, whereas he had signed it on 7 September, when he posted the notices, to surprise the sitting MPs and with the intention of returning his son. When the poll closed the numbers were as follows: Barry 386, Power 384, Carew 140, Hubbert 130. The inhabitants of the Manor of Dungarvan were supposed to amount to about 500, but 520 double votes had been cast. The committee concluded that the sitting MPs were duly elected, and the House endorsed their view.
In 1713 Brettridge Badham (0070) unsuccessfully challenged the return of James Barry (0093), the son of 0091, and in 1727 three members were returned - Benjamin Parry (1634), Thomas Carter (0360) and Robert Dillon (0636) - which was resolved by Carter being returned for Hillsborough, but not before a successful petition had been lodged. In this case the Sheriff, Thomas Uniacke (5029), had returned himself by illegally annexing an indenture to the return of the Returning Officer. In 1758, following the death of Robert Roberts (1794), Robert Boyle-Walsingham (0217) was returned to be unsuccessfully challenged by Sir William Osborne (1615), who withdrew his petition. There was also a complaint from the inhabitants that he did not know them sufficiently well and as a serving officer was likely to be an absentee.
Following the 1776 election John Bennett (0112) was returned, to be successfully challenged by Godfrey Greene (0901), who represented the constituency until 1790. The Ponsonby-Beresford pact came into force in 1790 and extended to Dungarvan,where in 1790 Marcus Beresford (0119) and Chambre Brabazon Ponsonby (1698) were returned, to be unsuccessfully challenged by Godfrey Greene and John Keily. In 1797 Marcus Beresford and John Brabazon Ponsonby (1703) were unsuccessfully challenged, this time by William Greene and John Keily. It was said that John Beresford (0115), Marcus's father, had imported the workers from the Customs House in Dublin to increase the vote. The result of the poll was: Beresford 144, Ponsonby 131, Greene 57, Keily 63. The return was made accordingly, but Greene threatened to petition against it.
Marcus Beresford died in 1797 and was replaced by Edward Lee (1211), who won the Union ballot for the single seat that Dungarvan retained. In 1799394 Dungarvan was described as 'Doubtful. Election in the inhabitants at large. The Beresford and Ponsonby families have lately returned each one Member. Frequently contested', and this had been the case throughout the century. After the Union the Devonshires endeavoured, with a measure of success, to recover slowly the electoral interest that they had neglected for so long.