Viscount Melbourne, of Kilmore in the County of Cavan, was a title in the Peerage of Ireland held by the Lamb family. This family descended from Matthew Lamb, who represented Stockbridge and Peterborough in the House of Commons. In 1755 he was created a baronet, of Brocket Hall in the County of Hertford, in the Baronetage of Great Britain. He married Charlotte, daughter of Thomas Coke, through which marriage Melbourne Hall in Derbyshire came into the Lamb family. The Honourable George Lamb, fourth and youngest son of the first Viscount, was also a politician.