Earl of Dartrey, of Dartrey in the County of Monaghan, was a title in the Peerage of the United Kingdom. It was created in July 1866 for The 3rd Baron Cremorne. Thomas Dawson, Burgess of Armagh, came from Yorkshire to Ireland during the reign of Elizabeth I. During the 1650s and 1660s, his second son, Richard, a cornet in Cromwell's cavalry, purchased 31 townlands which formed the nucleus of the family's estates in County Monaghan. His only daughter and heiress, Frances, married her cousin Walter Dawson (died 1718) of Armagh, who built Dawson's Grove, County Monaghan. Their son, Richard Dawson (died 1766), represented Monaghan County in the Irish House of Commons, becoming a Dublin banker and Alderman. He married Elizabeth Vesey, daughter of The Most Rev. Dr John Vesey, Church of Ireland Archbishop of Tuam and Lord Justice of Ireland. Richard's and Elizabeth's third son, Thomas Dawson, also sat as Member of Parliament for Monaghan County from 1749 to 1768 in the Parliament of Ireland. In 1770, he was raised to the Peerage of Ireland as Baron Dartrey, of Dawson's Grove in the County of Monaghan, and in 1785 he was made Viscount Cremorne, also in the Peerage of Ireland. Both titles were created with normal remainder to the heirs male of his body. In 1797 (after his three sons had all predeceased him) he was created Baron Cremorne, of Castle Dawson in the County of Monaghan (some sources claim "of Dawson-Grove in the County of Monaghan"), in the Peerage of Ireland, with remainder to his nephew Richard Dawson, Member of the British Parliament for County Monaghan from 1801 to 1807. On Lord Cremorne's death in 1813, the barony of Dartrey and the viscountcy became extinct. However, Viscount Cremorne was succeeded in the Barony of Cremorne, according to the special remainder, by his great-nephew Richard Thomas Dawson, the second Baron. He was the son of the above Richard Dawson. Lord Cremorne represented County Monaghan in the British House of Commons between 1812 and 1813. He was succeeded by his eldest son, the third Baron. In 1847 he was created Baron Dartrey, of Dartrey in the County of Monaghan, in the Peerage of the United Kingdom, which entitled him to an automatic seat in the House of Lords. He served as a government whip in the Liberal administrations of Lord Palmerston and Lord Russell. In 1866, he was further honoured when