Founded in 1829 in the city of Tullamore, located between Dublin and Galway, the Tullamore distillery has quickly risen to success over the years of its director D.E. Williams. Its initials were added to the name of the distillery, for those who were about to become the most famous assemblies of Irish Whiskey, Tullamore Dew. In 1954 the distillery closed its doors, but the brand was purchased by the Powers distillery which in 1875 became a member of the Irish Distillers group.

Tullamore D.E.W. XO respects the original recipe, with a blend of column and pot still from malted and non-malted spirits. It is distinguished by the aging in ex Rum Demerara barrels, inspired by the work of Irish immigrants in the Caribbean of the seventeenth century.