Back Anyos 1840 AN عقد 1840 Arabic عوام 1840 ARY عقد 1840 ARZ Década del 1840 AST 1840-cı illər Azerbaijani 1840-an BAN 1840-я Byelorussian 1840-я BE-X-OLD 1840-те Bulgarian
| 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. It is distinct from the decade known as the '''185st decade''' which began on January 1, 1841. and ended on December 31, 1850.