Henry John Reuben Dawson-Damer, 3rd Earl of Portarlington KP (5 September 1822 – 1 March 1889) was an Irish peer.

Henry Dawson-Damer, a Captain in the Royal Navy, and the former Eliza Moriarty, who lived at Milton Abbey, Dorset.

Edmund Joshua Moriarty and Lady Lucy Luttrell (daughter of the 1st Earl of Carhampton).

[3] The Earl was appointed a Knight of the Order of St Patrick on 8 February 1879.

[1] Lord Portarlington died, without issue, on 1 March 1889 and was succeeded in the earldom by his cousin, Lionel.