Baron Clermont is a title that has been created three times, twice in the Peerage of Ireland and once in the Peerage of the United Kingdom. All three creations are extinct. The first creation came in the Peerage of Ireland on 26 May 1770 for William Fortescue, who was later made Viscount and Earl of Clermont. 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 Clermont, formerly Member of Parliament for Louth, was made Baron Clermont, of Dromisken in the County of Louth, with remainder failing heirs male of his own to his younger brother Chichester Fortescue and the heirs male of his body.
Thomas Fortescue was the son of Chichester Fortescue, member of the Irish House of Commons for Hillsborough, son of Thomas Fortescue, member of the Irish Parliament for Trim, son of Chichester Fortescue, MP for Trim, grandson of Chichester Fortescue, whose brother William Fortescue was the grandfather of the aforementioned William Fortescue, 1st Earl of Clermont (see Viscount Clermont). Chichester Fortescue was the great-grandson of John Fortescue, husband of Susannah, daughter of Sir John Chichester and sister of Arthur Chichester, 1st Baron Chichester and Edward Chichester, 1st Viscount Chichester, ancestor of the Marquesses of Donegall (hence the common first name of Chichester). In 1866 Lord Clermont was also made Baron Clermont, of Clermont Park in the County of Louth, in the Peerage of the United Kingdom, with normal remainder to the heirs male of his body.