The son of Warner William Westenra, 2nd Baron Rossmore of Monaghan (1765–1842) by his marriage to Mary Ann Walsh, Henry Robert Westenra was born on 24 August 1792 at his mother"s family seat, Walsh Park in County Tipperary. On 10 August 1842, on the death of his father, he succeeded to the titles of Baron Rossmore of Monaghan in the peerage of Ireland and Baron Rossmore of Monaghan in the peerage of the United Kingdom, the second title giving him a seat in the House of Lords.
He was educated at Westminster School and Trinity College, Dublin, where he matriculated on 4 July 1810.
His portrait was painted the same year by John Ferneley (1782–1860), showing him with his dogs and carrying a shotgun. From 1843 to 1852 he was Lord Lieutenant of County Monaghan. In Twenty Years Recollections of an Irish Police Magistrate (1880), Frank Thorpe Porter recalled an evening when Rossmore
.. played several pieces of exquisitely sweet music, interspersed with the most extraordinary imitations.
In one, which was named The hare in the Corn, he produced sounds very much resembling the cry of the harriers, and other tones like the notes of a hunting horn, terminating with two or three simulated squeaks, supposed to indicate the capture of the hare.
In right of this wife Rossmore inherited an estate on the Scottish Isle of Arran. Frances Kathleen (died 1925)
Norah Josephine Harcourt (died 1934)
Henry Cairns Westenra, 4th Baron Rossmore (1851–1874)
Derrick Warner William Westenra, 5th Baron Rossmore (1853–1921)
Richard Hamilton (1854–1880)
Peter Craven (1855–1932).
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." He also reported that Rossmore had suffered from a very bad stammer. Rossmore died on 1 December 1860 at his country house in County Monaghan, Rossmore Park, and was buried there on 7 December 1860.
The house was abandoned in the 1940s, fell into a ruin, and was demolished in 1975.
6th United Kingdom Parliament. 7th United Kingdom Parliament. 8th United Kingdom Parliament.
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Westenra was Member of Parliament for County Monaghan from 1818 to 1830, again from 1831 to 1832 and from May to July 1834, and finally from 1835 to 1842.
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".
