- Oct 1 John Dunovant, US Confederate brigadier general, dies in battle
- Oct 1 Juan José Flores, General and first President of Ecuador (1839-1845), dies at 64
- Oct 1 Rose Greenhow, American Confederate spy (b. 1817)
- Oct 4 Joseph Montferrand, French Canadian logger and strong man, dies at 61
- Oct 7 Alexander Gardiner, US Union brigadier general, dies in battle
- Oct 7 John Gregg, American judge/Confederate brigadier general, dies in battle at 36
- Oct 8 Thomas Jonathan Coffin Amory, US Union-brigadier general, dies at about 34
- Oct 10 David Bullock Harris, US Confederate colonel, dies of yellow fever
- Oct 12 Roger B. Taney, 5th Chief Justice of the U.S. Supreme Court (1836-64) who delivered the majority Dred Scott decision, dies at 87
- Oct 18 David Bell Birney, American businessman, lawyer, and Major General (Union Army), dies at 39
- Oct 18 Jacques-François Gallay, French horn player and composer, dies at 68
- Oct 19 Daniel Davidson Bidwell, magistrate/brigadier general, dies in battle at 45
- Oct 20 Stephen Dodson Ramseur, American Major General (Confederate Army), dies at 27
- Oct 24 James Jay Archer, US Confederate brigadier general, dies in battle at 46
William T. Anderson (c. 1840-1864)
Oct 26 American Civil War Pro-Confederate rebel guerrilla leader (Lawrence Massacre, Centralia Massacre), killed in battle by union troops at 23 or 24
- Oct 27 Andreas Randel, Swedish composer, dies at 58
Assassination
Drug Overdose
Gunshot Wound
Murder
Plane Crash
Suicide