William Henry Fortescue (1722-1806), M.P. for co. Louth 1745-1770, for Monaghan (borough) 1761-1770, Post Master General 1764-1784, was created Baron Clermont in 1773, Viscount and Baron Clermont in 1776 and Earl of Clermont in 1777. He was Customer and Collector of the Port of Dublin from 1784 until his death. He married Frances Cairnes, first daughter and coheir of Colonel John Murray, M.P. for co. Monaghan, by Mary, Dowager Baroness Blayney. They died without issue.