The first creation came in the Peerage of Ireland in 1767 in favour of Robert Craggs-Nugent, who was made Viscount Clare at the same time.
For further history of this creation, see Earl Nugent and Viscount Cobham.
The second creation came in the Peerage of Ireland in 1800 when Mary, Marchioness of Buckingham, was made Baroness Nugent, of Carlanstown in the county of Westmeath, with remainder to her second son Lord George Nugent-Grenville.
She was the daughter of the first Earl Nugent and the wife of George Nugent-Temple-Grenville, 1st Marquess of Buckingham.
She was succeeded according to the special remainder by her younger son, Lord George, the second Baron.