MAHON, Hon. Stephen (1768-1828), of Strokestown, co. Roscommon.

Published in The History of Parliament: the House of Commons 1790-1820, ed. R. Thorne, 1986
Available from Boydell and Brewer



1806 - 1826

Family and Education

b. 6 Feb. 1768, 2nd s. of Maurice, 1st Baron Hartland [I], by Hon. Catherine Moore, da. of Stephen, 1st Visct. Mount Cashell [I]; bro. of Hon. Thomas Mahon. unm.

Offices Held

MP [I] 1800.

Ensign, 47 Ft. 1786, lt. 1790; capt. 5 Drag. 1791; maj. 7 Drag. 1793, brevet lt.-col. 1796; lt.-col. 7 Drag 1797, brevet col. 1805; lt.-col. 8 Drag. 1808, maj.-gen. 1810; lt.-gen. 1819.


Like his elder brother Thomas, Mahon was an army officer. He was brought into the Irish parliament for Knocktopher by his father in May 1800 ‘at very great expense’ to support the Union, ‘which he did effectively’.1 In 1806, in the absence of his elder brother, his father put him up for the county and he displaced Edward King, without a contest. The Grenville ministry were ‘doubtful’ of him2 and in April 1807 he voted with their successors, the Portland administration. In 1808 he was listed as a supporter of government and reported to have as his main object promotion in the Irish peerage for his father, who claimed previous promises of it. The chief secretary proposed to keep Mahon quiet by military promotion.3 On 5 and 25 May 1808 he voted for the Catholic claims, while on, 17 Mar. 1809 he was in the minority against Perceval on the Duke of York’s misconduct of army patronage, as also 25 Apr., on Castlereagh’s alleged corruption. He voted with ministers on the Scheldt expedition, 26 Jan., 30 Mar. 1810, and opposition were ‘doubtful’ of his sympathy at that time, though he again voted for Catholic claims on 1 June 1810 and 31 May 1811 and, to the annoyance of the Castle, for Morpeth’s Irish motion of 4 Feb. 1812.4 The Castle also noted that he had left the House without dividing on the Regency question, 21 Jan. 1811, having avoided earlier debates on the matter.5

Although Mahon continued to vote for Catholic relief, 24 Apr. 1812, 2 Mar. 1813 (pairing because of illness on 13 May), 30 May 1815, 21 May 1816, 9 May 1817 and 3 May 1819, he was otherwise a government supporter until June 1819, despite his father’s disappointment at not getting a viscountcy. In 1815 the latter directed him to complain about this, pointing out that Mahon ‘has constantly attended and supported government both in England and here without any favour from government’. He advised:

Now I would have you promise to support any measure recommended by government consistent with your duty as a county Member provided I was to be promoted to a viscount here.

In 1816 Mahon was appointed to the Irish staff, in command of the western district, and this was his excuse for absence from Parliament in January 1817. In 1819 his father died unpromoted and his brother Thomas did not fare any better. This and ‘removal from staff’ were reported by the Castle to be the reasons for Mahon’s ceasing to support government.6 He was in the minorities on public income, 7 June, the foreign enlistment bill, 10 June, the state of the country, 30 Nov., and the seditious meetings bill, 2, 6 Dec. 1819. No speech is known. Mahon died 27 May 1828.

Ref Volumes: 1790-1820

Author: P. J. Jupp


  • 1. PRO 30/9/1, pt. 3/2, Hardwicke to Abbot, 21 Nov. 1801.
  • 2. NLS mss 12925, Irish list; Fremantle mss, box 46, Buckingham to Fremantle, 16 June [1807].
  • 3. Add. 40221, ff. 13-42; NLI, Richmond mss, Wellesley to Richmond, 19 May 1808.
  • 4. Richmond mss 67/1019.
  • 5. Ibid. 64/727a; 65/738.
  • 6. Add. 40250, f. 326; 40262, f. 264; 40298, f. 37.