In 1790 it was said that 'This district, neither great in extent, rich in cultivation, nor thickly peopled, is distinguished in the election annals of the kingdom, by being the only County, we remember, where the representative of it carried his election by the majority of a single vote. This circumstance took place at the time when the late Hon. Robert Pakenham, Lord Longford's brother, was chosen for it and was a remarkable proof of the equipoise of interest of great contending families, for we must be allowed to assert, that the affections of the Freeholders and still less their sober judgements, were very little concerned in the contest.'259 This was the general election of 1768, when the Dublin Journal (2-4 August) reported that 'At the close of the poll for the Members for Co. Longford, the numbers were as follows for: Col. Gore 401, Mr Pakenham 283, Sir James Nugent 281, Sir Thomas Newcomen 2?8.' This gives a majority of two: perhaps one was disqualified. Sir James Nugent petitioned against the return, but withdrew his petition.
Two branches of the Newcomens, which had had considerable influence early in the century, died out in the male line in the 1770s and 1780s but their heiress, Charlotte, married the banker Sir William Gleadowe who, following a well-established custom, added Newcomen to his name; along with their name he acquired their interest. When, in 1789, Henry Gore received his long-awaited peerage, which had kept the county in a state of expectation for the previous four or five years, Sir William Gleadowe-Newcomen was elected in his place for the three remaining months of the 1783-90 parliament. He was again returned in 1790, and sat until after the Union.
In 1785 it was considered that 'Lord Longford (1619), Colonel Gore and Mr Harman have the chief interests.'260 The Harman-Sheppard-Parsons interest was a major element in Co. Longford politics through the century. It was linked by a complicated set of marriages and inheritance (see 0971, 1912), which eventually coalesced in Sir Laurence Parsons (1636), who also had the remainder to the titles Lord Oxmantown and finally Earl of Rosse, conferred on Laurence Harman (Parsons) Harman between 1792 and 1806. The Earls of Longford tended to concentrate on their borough, although Edward and Robert Pakenham sat briefly for the county - for about six years in all. The Forbeses, Earls of Granard, concentrated on St Johnstown. Sir Ralph Fetherston sat for only three years, although with the support of the Parsonses the Fetherstons staged a comeback starting in 1796 and continuing after the Union, while the Forbes also became more politically prominent in the post-Union parliaments.
Co. Longford had four boroughs: Granard, Lanesborough, Longford and St Johnstown.