It was created in 1781 for James Hewitt, 1st Baron Lifford, the Lord Chancellor of Ireland.
His grandson, the fourth Viscount, sat in the House of Lords as an Irish representative peer from 1856 to 1887.
His younger son, the sixth Viscount (who succeeded his elder brother), was a captain in the Royal Navy.
George Wyldbore Hewitt, seventh son of the fourth Viscount.
As of 2014[update] the titles are held by his son, the ninth Viscount, who succeeded in 1987.