The Parnell Baronetcy of Rathleague in the Queen's County was created in the Baronetage of Ireland on 3 November 1766 for the first Baron's grandfather, John Parnell. He represented Maryborough in the Irish Parliament. His son, the second Baron, sat as a Member of the Irish House of Commons for Queen's County and served as Chancellor of the Exchequer in Ireland. His younger son was the aforementioned fourth Baronet, who was raised to the peerage in 1841.
Another member of the Parnell family was Charles Stewart Parnell. He was a grandson of William Parnell-Hayres, third son of the second Baronet.