For more information on this creation see Viscount Clermont, a title which became extinct in 1829.
The second creation came in the Peerage of Ireland on 11 February 1852 when Thomas Fortescue, formerly Member of Parliament for Louth, was made Baron Clermont, of Dromisken in the County of Louth, with special remainder failing heirs male of his own to his younger brother Chichester Fortescue and the heirs male of his body.
He died childless in 1887 when the barony of 1866 became extinct while he was succeeded in the barony of 1852 according to the special remainder by his younger brother, Chichester Fortescue, who in 1863 had assumed the additional surname of Parkinson.
He was a Liberal politician and had already been raised to the Peerage of the United Kingdom in his own right as Baron Carlingford, of Carlingford in the County of Louth, on 28 February 1874, with normal remainder to heirs male.
Sir Chichester Fortescue, son of Chichester Fortescue, MP for Trim, was a Rear-Admiral in the Royal Navy and member of the Irish Parliament for Trim.