Newry was incorporated in 1612/3 by a charter of 10 James I following the petition of 'the inhabitants of the town of Newry in the county of Down'. It was to be a free borough with a provost and 12 free burgesses and the commonalty, with the power of sending two members to parliament. It developed into a potwalloping borough with a comparatively large electorate of 600-700 voters. The dominant interest was that of the Nedhams (Needhams) of Mourne Park. Robert Nedham (1518) sat for Newry from 1727 until his death in 1753. He was co-heir with Edward Bayly of the estates of Nicholas Bagenal, who appears to have possessed the manors of Newry, Mourne and Carlingford. Newry and Mourne came to Nedham. After the opening of the canal joining Newry with Lough Neagh, the commercial prospects of the town improved and Nedham was anxious to build a Customs House on the Quay. Lord Hillsborough had a bleach yard near Mill Street and was also anxious to improve the economic prospects of the town. Nedham's son and namesake (1519) succeeded him and sat for Newry from 1753 to 1760. He was a British MP and a brother-in-law of William Pitt; his interests were divided between the British and Irish parliaments. His sons, George (1517) and William (1520), sat for Newry; George Nedham from 1761 until his death in 1767 and William Nedham consecutively from 1767 until 1776, but William was more involved in British than Irish politics. The Nedham interest then appears to have been neglected or at least subsidiary to their other interests, which included a plantation in Jamaica, until after the Union.
The vacuum was filled by local men, especially the Rosses of Rostrevor, whose estate stretched around Newry from Rostrevor to Rathfriland. The Ross family also had an interest in Dublin city politics, and Robert Ross (1814) was an alderman of Dublin. He was first returned for Killyleagh in 1715 and then for Newry in 1727, which he represented until his death in 1750. His son Robert (1815), who was Lord Mayor of Dublin in 1749, returned himself for nearby Carlingford from 1723 to 1768, so father and son sat in parliament together. The third-generation Robert (1816) returned himself for Carlingford from 1768 to 1776, but in 1776 was returned for Newry, which he represented until his death in 1799. He was a colonel in the army and afterwards a Commissioner of the Revenue. He was unmarried, and in 1796 he sold his half-interest in Carlingford to the Marquess of Downshire (1016). There was always in the background the infiltrating influence of the Marquess of Downshire.
The vacuum caused by the de facto absence of the Nedham interest resulted in the rise of two local men. Robert Scott (1892) was first returned for Newry in 1751, at a by-election following the death of Robert Ross. He sat for Newry from 1751 to 1760 and again from 1768 until his death in 1773. It was said that 'By living here and pleasing the people he established an interest for himself. He built a number of houses in the town. Trustee of the Linen Board' - the last was important as Newry's prosperity was linked to the linen manufacture. It was also noted that he: 'brings himself into parliament. A merchant of Newry and Independent.' He died in 1773 and another merchant, Edward Corry (0495), was returned at the expensive and fiercely contested double (the first election was declared void) by-election, in the course of which one man was killed. At the first election Sir Richard Johnston (1110) challenged the return; the final poll for the second election was Edward Corry 329 and John Bowes Benson 268. Edward Corry was declared duly elected.
In 1776 Edward Corry stood aside for his son, Isaac Corry (0497). Corry was agent to the Nedhams and could be said to have come in with their support. Robert Ross was returned with him, and they were both unsuccessfully challenged by Sir Richard Johnston and John Bowes Benson. Isaac Corry sat for Newry until the Union, when he lost the ballot to John Moore (1464), who had recently been returned, through the influence of Lord Downshire, at the by-election following the death of Robert Nedham in 1799. Corry was Chancellor of the Irish Exchequer, and his failure to win the ballot caused consternation in government circles. In 1802 Lady Downshire, who declared that 'These were not the steps by which my dearest lord and his father acquired their influence in the county of Down', only withdrew her support for Moore after considerable pressure from the government, thus allowing Corry to be returned unopposed at the general election. Newry had major interests, but if they were neglected the comparatively large electorate could allow lesser interests, at least temporarily, to slide through the cracks.