Charles Henry St John O'Neill, 1st Earl O'Neill, KP, PC (I) (22 January 1779 – 12 February 1841) was an Irish politician, peer and landowner. He was born in 1779 to John O'Neill, 1st Viscount O'Neill, of Shane's Castle, County Antrim, Ireland, and educated at Eton before joining Christ Church, Oxford on 23 November 1795. He succeeded as second Viscount O'Neill in 1798 on the death of his father and was made Viscount Raymond and Earl O'Neill in 1800 after the Act of Union, when it was decided that O'Neill should have precedence in the Irish peerage. After the passing of the act he was elected as one of the 28 Irish peers allowed to sit in the House of Lords in September 1800. In 1807 he was appointed one of the joint Postmasters General of Ireland along with Richard Trench, 2nd Earl of Clan