April 19, 1861
Bombardment of Fort Sumter, immediate cause and first battle of the American Civil War
Reform War — 1858–1861 internal conflict in Mexico
1861 battle of the Trans-Mississippi Theater of the American Civil War
Battle between Sioux and Crow
Emancipation reform of 1861 — reform passed by Tsar Alexander II of Russia which effectively abolished serfdom throughout the Russian Empire
Part of the American Civil War in New Mexico Territory (1861)
1861 treaty between the United States and representatives of the Cheyenne and Arapaho
Battle in the American civil war
1861 early battle of the American Civil War