1861 was a common year starting on Tuesday of the Gregorian calendar.
|Centuries:||18th century – 19th century – 20th century|
|Decades:||1830s 1840s 1850s – 1860s – 1870s 1880s 1890s|
|Years:||1858 1859 1860 – 1861 – 1862 1863 1864|
- The American Civil War begins.
- January 1 - Benito Juárez captures Mexico City.
- March 19 – The First Taranaki War ends in New Zealand.
- August 19 – First ascent of Weisshorn, fifth highest summit in the Alps.
- September – The first complete identified remains of Archaeopteryx are discovered in Germany.
- for more information, see Category:1861 births.
- for more information, see Category:1861 deaths.