1819 in the United Kingdom
- Monarch – George III
- Prime Minister – Robert Jenkinson, 2nd Earl of Liverpool (Tory)
- Parliament – 6th
- 6 February – formal treaty between Sultan Hussein of Johor and the British Sir Stamford Raffles establishes a trading settlement in Singapore.
- 19 February – William Smith discovers the South Shetland Islands.
- 20 March – Burlington Arcade opens in London.
- 14 April – the streets of Birmingham are lit by gas for the first time by the Birmingham Gas Light and Coke Company.
- 21 April–end May – John Keats writes La Belle Dame sans Merci and most of his major odes.
- 20 June – the SS Savannah, the first steamship to cross the Atlantic Ocean, arrives at Liverpool from Savannah, Georgia, United States, although only a fraction of the trip is made under steam.
- June – Act of Parliament to abolish private appeals following acquittals in criminal cases and to abolish trial by combat, in the aftermath of Ashford v Thornton (1818).
- 16 August – Peterloo Massacre in St. Peter's Field, Manchester: a cavalry charge into a crowd of protesters results in eleven deaths and over 400 injuries.
- 19 September – Keats writes his ode To Autumn at Winchester.
- Britannia Monument to Admiral Lord Nelson at Great Yarmouth (the "Norfolk Pillar") is completed.
- The Travellers Club is established in London.
- John Polidori's short story The Vampyre.
- Walter Scott's novels Ivanhoe, The Bride of Lammermoor and A Legend of Montrose.
- 8 February – John Ruskin, writer, artist and social critic (died 1900)
- 11 March – Sir Henry Tate, 1st Baronet, sugar merchant and philanthropist (died 1899)
- 28 March – Joseph Bazalgette, civil engineer (died 1891)
- 24 May – Queen Victoria, born Princess Alexandrina Victoria of Kent, queen regnant (died 1901)
- 5 June – John Couch Adams, astronomer (died 1892)
- 12 June – Charles Kingsley, novelist (died 1875)
- 1 August – Richard Dadd, painter (died insane 1886)
- 13 August – Sir George Stokes, 1st Baronet, Irish-born mathematician and physicist (died 1903)
- 26 August – Albert, Prince Consort to Queen Victoria (born at Coburg; died 1861)
- 5 September – stillborn child to the Duke of Clarence and Adelaide of Saxe-Meiningen (born dead at Calais)
- 22 November – George Eliot, born Mary Ann Evans, novelist (died 1880)
- 25 August – James Watt, Scottish-born inventor (born 1736)
- 22 November – John Stackhouse, botanist (born 1742)
- 19 December – Sir Thomas Fremantle, naval officer and politician (born 1765; died at Naples)
- Penguin Pocket On This Day. Penguin Reference Library. 2006. ISBN 0-14-102715-0.
- Keats, John (1973). Barnard, John, ed. The Complete Poems. Harmondsworth: Penguin Education. ISBN 0-14-080668-7.
- Megarry, Robert (2005). A New Miscellany-at-Law. Oxford: Hart. ISBN 978-1-58477-631-4.
- "Icons, a portrait of England 1800–1820". Archived from the original on 17 October 2007. Retrieved 2007-09-11.
- Ziegler, Philip (1971). King William IV. London: Collins. p. 126. ISBN 0-00-211934-X.