Richard Somerset Le Poer Trench, 4th Earl of Clancarty (13 January 1834 – 29 May 1891), styled Viscount Dunlo between 1837 and 1872, was an Irish peer.
Trench was born in Dublin, Ireland, the son of William Trench, 3rd Earl of Clancarty and Lady Sarah Juliana Butler. On 29 November 1866 he married Lady Adeliza Georgiana Hervey, daughter of Frederick William Hervey, 2nd Marquess of Bristol and Lady Katherine Isabella Manners. They had three children.
| Peerage of Ireland | ||
|---|---|---|
| Preceded by William Thomas Le Poer Trench |
Earl of Clancarty 1872–1891 |
Succeeded by William Frederick Le Poer Trench |