Background
Rosse was the second son of Sir Lawrence Parsons, 3rd Baronet, of Birr Castle, by his wife Anne, daughter of Wentworth Harman.
Rosse was the second son of Sir Lawrence Parsons, 3rd Baronet, of Birr Castle, by his wife Anne, daughter of Wentworth Harman.
In 1795 he was made Viscount Oxmantown, of Oxmantown in the County of Dublin, also in the Peerage of Ireland but with normal remainder to the heirs male of his body. Lord Oxmantown was even further honoured in 1806 when he was created Earl of Rosse in the Irish peerage, with similar remainder as for the barony. From 1800 to 1807 he sat in the House of Lords sat as one of the 28 original Irish Representative Peers.
Lord Rosse married Lady Jane, daughter of Edward King, 1st Earl of Kingston, in 1772.
He was a Member of the Irish House of Commons for Longford County from 1775 to 1792 and for County Longford from 1790 to 1792.