Mullingar was a curious borough. It was a manor set up by royal letters of 1583, 25 Eliz. I. There was also a 1676 charter of 27 Chas II but this was a grant to Sir Arthur Forbes, his heirs and assigns, 'to grant any of the lands of the Manor of Mullingar as he shall think fit'; the freeholders were to return two members to parliament. From then until the Union Sir Arthur Forbes and his descendants, Earls of Granard, controlled the return of the MPs for Mullingar. In 1790 it was explained that:
The constitution of this manor is peculiarly singular. It was created at the Revolution, in favour of the Earl of Granard, in exclusion of the families of Pettit and Dalton, who had before a commanding influence in the ancient Borough and the Crown, to mark its sense of his eminent services, irrevocably fixed the absolute power of election in the Earl, by a most remarkable clause in the charter, directing that none should enjoy the right of suffrage or franchise in the manor, except Freeholders immediately created by the Earl, and his successors.423
Mullingar was an important market town and in 1783 it was said that the electorate consisted of 'Sovereign and Freeholders of the Manor, about 12 in number. But one elector in the town. 2,000 inhabitants, 100 Protestants. Patron, Lord Granard. A large town.'424Various members of the family sat for it, particularly in the middle of the century (1749-68). It was disfranchised in 1800; the £15,000 compensation was paid to George, Earl of Granard.