Rathcormack was a combination of a potwalloping and a manor borough incorporated by charter, which was produced at the Union. Some boroughs, particularly those enfranchised before or during the early years of the seventeenth century, evolved differently from the way their founders had envisaged: Rathcormack, which had been a manor borough, acquired a potwalloping aspect over time, but remained tied to the borough and its surrounding area. The franchise was vested in the £5 and, until 1793, protestant freeholder; after 1782 a year's residence was necessary.
Rathcormack had belonged to the Barry family, who owned the manor but neglected the borough. In the early 1770s it was said that James Barry (0094) 'had the natural interest here but his father being idle and negligent and he not much better the interest has almost gone'. Sometime in the middle of the century Abraham Devonsher (0627) established an interest in it 'by constantly residing and entertaining and drinking with the people. It is [c. 1772] a potwalloping borough. He was a Quaker and read out of Meeting. He lives a recluse life with a harlot. Is totally independent but wishes Lord Shannon well.' But in 1775 Lord Shannon wrote to James Dennis (0613) that 'with respect to Devonsher I know of few men whose friendship is less worth cultivating. He was always supported by my father and by me as you know and now he will not attend the last time he [did, he] was very near voting against us.'126 About 1774 James Barry sold 'the Rathcormack estate and borough' to William Hull Tonson (1051), Richard Tonson's (2083) illegitimate son and heir,and Tonson swiftly and completely reasserted the influence of the Lord of the Manor of Rathcormack - only seven voted in 1783 and in 1800 his son, or the son's guardians, received the £15,000 compensation for its disfranchisement.