- Oct 1 Claudius Charles Wilson, American Brigadier General (Confederate Army), born in Effingham County, Georgia (d. 1863)
- Oct 6 Richard Dedekind, German mathematician (Nature & Meaning of Numbers), born in Braunschweig, Germany (d. 1916)
- Oct 15 Helen Hunt Jackson, American author (Ramona), born in Amherst, Massachusetts (d. 1885)
- Oct 18 Frederick III, German Emperor (1888), born in Potsdam, Kingdom of Prussia (d. 1888)
- Oct 31 Daniel Butterfield, American Major General (Union Army), assistant US Treasurer, born in Utica, New York (d. 1901)
- Oct 31 Paolo Mantegazza, Italian neurologist and anthropologist, born in Monza, Italy (d. 1910)