1840s

Millennium:	2nd millennium
Centuries:	18th century – 19th century – 20th century
Decades:	1810s 1820s 1830s – 1840s – 1850s 1860s 1870s
Years:	1840 1841 1842 1843 1844 1845 1846 1847 1848 1849
Categories:	Births – Deaths – Architecture; Establishments – Disestablishments

The 1840s was the decade that began on January 1, 1840 and ended on December 31, 1849.

Events

First Opium War: British ships approaching Canton in May 1841
Depiction of the signing of the Treaty of Waitangi in 1840, bringing New Zealand and the Māori into the British Empire
A memorial of Matale Rebellion, which began in Sri Lanka in 1848
Map of Europe in 1848–1849 depicting the main revolutionary centers
April 10: "Monster Rally" of Chartists held on Kennington Common in London; the first photograph of a crowd depicts it.
September 12: The Swiss Confederation reconstitutes itself as a federal republic.
The frigate Belle-Poule brings back the remains of Napoleon to France.

Millennium:	2nd millennium
Centuries:	18th century – 19th century – 20th century
Decades:	1810s 1820s 1830s – 1840s – 1850s 1860s 1870s
Years:	1840 1841 1842 1843 1844 1845 1846 1847 1848 1849
Categories:	Births – Deaths – Architecture Establishments – Disestablishments