1839 in the United Kingdom
- January – the first parallax measurement of the distance to Alpha Centauri is published by Thomas Henderson.
- 19 January – British East India Company captures Aden.
- 25 January – H. Fox Talbot shows his "photogenic drawings" at the Royal Institution in London. Sara Anne Bright is also producing such photographic reproductions this year.
- 29 January – naturalist Charles Darwin marries his cousin Emma Wedgwood at Maer, Staffordshire.
- February – Report on the Affairs of British North America published.
- 26 February – first nationally recognised Grand National run, at Aintree. It is won by Jem Mason riding Lottery.
- 26 March – the first Henley Royal Regatta is held on the River Thames.
- 9 April – the world's first commercial electric telegraph line comes into operation alongside the Great Western Railway line from London Paddington station to West Drayton.
- 19 April – the Treaty of London establishes Belgium as a kingdom with its independence and neutrality guaranteed by Britain and the other great powers of Europe.
- 1 May – start of Eyre's expeditions to the interior of South Australia.
- 7–11 May – Bedchamber Crisis: Robert Peel asks that Queen Victoria dismiss her Ladies of the Bedchamber as a condition for his forming a government. Victoria refuses to accept the condition, and Melbourne is persuaded to stay on as Prime Minister.
- 13 May – first Rebecca Riots targeted against Welsh turnpikes, at Efailwen in Carmarthenshire.
- 31 May – important British constitutional case of Stockdale v Hansard is launched when publisher John Joseph Stockdale sues for libel after John Roberton's pseudo-medical work On Diseases of the Generative System (1811) is declared in a parliamentary report to be indecent.
- 3 June – destruction of opium at Humen begins, casus belli for Britain to open the 3-year First Opium War against Qing dynasty China.
- 4 July – Chartists riot in Birmingham.
- 15 July – first clipper ship launched in Britain, the schooner Scottish Maid at Alexander Hall's yard in Aberdeen.
- 23 July – British forces under Sir John Keane capture the fortress city of Ghazni, Afghanistan in the Battle of Ghazni during the First Anglo-Afghan War.
- 23 August – British forces seize Hong Kong as a base, as it prepares to wage the First Opium War.
- 30 August – the Eglinton Tournament, a recreation of a medieval tourney, takes place at Eglinton Castle, North Ayrshire, Scotland.
- 5 October – James Clark Ross sets out on the Antarctic expedition of the HMS Erebus and HMS Terror which will chart much of the coastline of the continent.
- 19 October – George Bradshaw publishes the first national railway timetable, Bradshaw's Railway Time Tables and Assistant to Railway Travelling, in Manchester.
- 4 November – Newport Rising: several thousand coal miners march on Newport, Monmouthshire, to liberate Chartist prisoners; 24 killed.
- November – launch of the first British ocean-going iron warship, Nemesis for the East India Company, by William Laird at Birkenhead.
- 5 December – Uniform Fourpenny Post introduced, a major postal reform, whereby 4d is levied for pre-paid letters up to half an ounce in weight instead of postage being calculated by distance and number of sheets of paper.
- 24 December – an enormous landslide occurs at Axmouth, Devon. A report by geologists William Daniel Conybeare and William Buckland is one of the earliest scientific descriptions of such an event.
- New Committee of Council on education sets up a national system of Inspectors of Schools.
- County Police Act enables the appointment of police in rural areas and City of London Police Act confirms establishment of a force in the City.
- Custody of Infants Act (based largely on campaigning by Caroline Norton) permits limited rights of custody of young children to divorced mothers.
- Sisters of Mercy establish the first Roman Catholic convent in England since the Reformation, at Bermondsey in London.
- Michael Faraday publishes Experimental Researches in Electricity clarifying the true nature of electricity.
- Claimed invention of the rear-wheel driven bicycle by Kirkpatrick Macmillan in Scotland.
- Philip James Bailey's (anonymous) poem Festus.
- Charles Darwin's Journal of Researches into the Geology and Natural History of the Various Countries Visited by H.M.S. Beagle under the Command of Captain FitzRoy, R.N., from 1832 to 1839.
- Mrs William Ellis's conduct book The Women of England: their social duties and domestic habits.
- 7 January – Ouida (Maria Louise Ramé), novelist (died 1908)
- 16 March – John Butler Yeats, Irish artist (died 1922)
- 17 June – Arthur Tooth, Anglican clergyman prosecuted for Ritualist practices in the 1870s (died 1931)
- 19 September – George Cadbury, businessman (died 1922)
- 22 December – John Nevil Maskelyne, stage magician (died 1917)
- 16 January – Edmund Lodge, writer (born 1756)
- 28 January – William Beechey, portrait-painter (born 1753)
- 11 April – John Galt, novelist (born 1779)
- 17 May – Archibald Alison, author (born 1757)
- 24 December – James Smith, author (born 1775)
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- "National Army Museum : Exhibitions : Afghanistan". Retrieved 2007-09-12.
- "John Lovell and the People's Charter, National Archives". Retrieved 2007-09-12.
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- "Axmouth to Lyme Regis: The Undercliff, The Jurassic Coast World Heritage Site". Retrieved 2007-09-12.
- Berry, George (1970). Discovering Schools. Tring: Shire Publications. ISBN 0-85263-091-3.
- Friar, Stephen (2001). The Sutton Companion to Local History (rev. ed.). Stroud: Sutton Publishing. p. 243. ISBN 0-7509-2723-2.
- Nelson, Sioban (2001). Say Little, Do Much: Nursing, Nuns and Hospitals in the Nineteenth Century. Philadelphia: University of Pennsylvania Press. ISBN 978-0-8122-3614-9.
- "Experimental Researches in Electricity". Retrieved 2007-09-12.
- "Kirkpatrick Macmillan (1812–1878)". Historic Figures. BBC. Retrieved 2011-02-12.
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