Events from the year 1811 in the United Kingdom. This is a census year and the start of the British Regency.

• Monarch – George III
• Regent – George, Prince Regent (starting 5 February)
• Prime Minister – Spencer Perceval (Tory)
• Foreign Secretary – Richard Wellesley, 1st Marquess Wellesley
• Home Secretary – Richard Ryder

• 1 February – Bell Rock Lighthouse begins operation off the coast of Scotland.^[1]
• 5 February – George, Prince of Wales becomes Regent^[1] under terms of the Regency Act because of the perceived insanity of his father, King George III.^[2] He is known as the Prince Regent and this is the beginning of the Regency period.^[3]
• 21 February – The John and Jane, carrying troops bound for the Peninsular War, is accidentally run down and sunk by HMS Franchise off Lizard Point, Cornwall with the loss of a majority of the 300 on board.^[4]
• 22 February – Editor Leigh Hunt and his publisher brother John, defended by Henry Brougham, are cleared of seditious libel over a September 1810 article in their newspaper, The Examiner, criticising flogging in the Army.^[5]
• 13 March – Battle of Lissa: British fleet defeats the French.
• 25–27 March – Battle of Anholt: British naval forces defeat those of Denmark.
• 4 April – Huddersfield Narrow Canal completed by opening of Standedge Tunnel under the Pennines, the longest (5,413 yards (4,950 m)), deepest and highest canal tunnel in Britain.^[6]
• 27 May – The second national Census reveals that the population of England and Wales has increased in ten years by over a million to 10.1 million.^[7]
• 10 June – A volcanic eruption, observed from Royal Navy sloop HMS Sabrina (1806), creates Sabrina Island (Azores) which on 4 July is claimed for Britain; a few months later it sinks beneath the sea.
• 18 June – The Welsh Calvinistic Methodists leave the established Church of England by ordaining their own ministers in Bala, North Wales.
• 19 June – The Carlton House Fête is held at Carlton House in London. A costly and extravagant event it celebrated the beginning of the Regency era.
• 8 September – The first known landing on Rockall is made by a party from HMS Endymion.^[8][9]
• 16 October – National Society for Promoting the Education of the Poor in the Principles of the Established Church in England and Wales established by the Church of England to promote a system of National Schools.
• November – Luddite uprisings begin in northern England and Midlands.^[10]
• 4 December – Royal Navy frigate HMS Saldanha (1809) is driven in a gale onto rocks in Lough Swilly in Ireland with no survivors from the estimated 253 aboard.^[11]
• 7–19 December – Ratcliff Highway murders in London.
• 24 December – Christmas Eve storm in the North Sea leads to wreck of HMS St George, Defence and Fancy off Jutland; and HMS Hero and the transport Archimedes off Texel with the loss of nearly 2,000 men.^[12]

• Napoleonic Wars, 1803–1815
• Anglo-Russian War, 1807–1812
• Anglo-Swedish War 1810–1812
• Peninsular War, 1808–1814

• Highland Clearances: The Marquess and Marchioness of Stafford begin mass expulsion of crofting tenants from their Highland estates to make way for sheep farming.^[13][14]
• Building of Regent Street begins John Nash's development of the West End of London.^[15]
• The first complete ichthyosaur fossil is found by Mary Anning at Lyme Regis.

• Jane Austen's novel Sense and Sensibility ('by a lady').
• Francis Place's Illustrations and Proofs of the Principles of Population, including an examination of the proposed remedies of Mr. Malthus, and a reply to the objections of Mr. Godwin and others, the first significant text in English to advocate contraception.^[16]

• 9 January – Gilbert Abbott à Beckett, writer (died 1856)
• 1 February – Arthur Hallam, poet (died 1833)^[17]
• 6 February – Henry Liddell, academic and cleric (died 1898)
• 24 February – Edward Dickinson Baker, United States Senator from Oregon from 1860 (died 1861 in the United States)
• 21 March – Nathaniel Woodard, educationalist (died 1891)^[18]
• 7 June – James Simpson, Scottish obstetrician and pioneer of anaesthesia (died 1870)
• 13 June – Owen Stanley, Royal Navy officer (died 1850)
• 11 July – William Robert Grove, Welsh chemist, inventor (died 1896)^[19]
• 13 July
  • George Gilbert Scott, architect (died 1878)
  • James "paraffin" Young, Scottish chemist (died 1883)^[20]
• 18 July – William Makepeace Thackeray, novelist (died 1863)
• 14 September – William Budd, physician and epidemiologist (died 1880)^[21]
• 31 October – William Loring, admiral (died 1895)^[22]
• 8 November – John Tarleton, admiral (died 1880)^[23]
• 21 December – Archibald Campbell Tait, Archbishop of Canterbury (died 1882)

• 9 February – Nevil Maskelyne, Astronomer Royal (born 1732)
• 24 February – James Brudenell, 5th Earl of Cardigan, politician (born 1715)^[24]
• 14 March – Augustus FitzRoy, 3rd Duke of Grafton, Prime Minister of Great Britain (born 1735)^[25]
• 4 April – Mary Woffington, Irish socialite (b. 1729)^[26]
• 5 May – Robert Mylne, architect (born 1734)^[27]
• 7 May – Richard Cumberland, dramatist (born 1732)
• 28 May – Henry Dundas, 1st Viscount Melville, Scottish politician, Home Secretary for Great Britain (born 1742)^[28]
• 29 July – William Cavendish, 5th Duke of Devonshire (born 1748)^[29]
• 30 September – Thomas Percy, poet, ballad collector and bishop (born 1729)^[30]
• 15 October – Sir Nathaniel Dance-Holland, portrait painter and politician (born 1735)
• 27 November – Andrew Meikle, Scottish mechanical engineer (born 1719)^[31]
• 21 December – Sir Peter Parker, 1st Baronet, Admiral of the Fleet (born 1721 in Ireland)
• 31 December – Benjamin Vulliamy, clockmaker (born 1747)