Henry Robert Westenra, 3rd Baron Rossmore (24 August 1792 – 1 December 1860), was an Anglo-Irish Member of Parliament and hereditary peer, from 1843 to 1852 Lord Lieutenant of Monaghan.

[2] A member of a family of individualists, Rossmore was a prolific letter-writer, and his surviving letters have been described as "voluminous, frequently vitriolic, and very instructive".

recalled an evening when Rossmore ... played several pieces of exquisitely sweet music, interspersed with the most extraordinary imitations.

[4] On 19 May 1846, after the death of his first wife, Rossmore married secondly at Camla Vale, County Monaghan, his cousin Josephine Julia Helen (née Lloyd), with whom he had six children: According to Rossmore's second son, the fifth baron, "My father's favourite amusements were yachting, shooting and fishing, and, oddly enough, playing the bagpipes, at which he excelled."

[4] His granddaughter Kathleen (1872–1955), married The 7th Duke of Newcastle in 1899 and was a dog breeder who influenced the Borzoi and Wire Fox Terrier breeds.