- Oct 1 Jeremiah Cutler Sullivan, American Brigadier General (Union Army), born in Madison, Indiana (d. 1890)
- Oct 3 George Brayton, American engineer who developed the Brayton Cycle combustion engine, born on Rhode Island (d. 1892)
- Oct 9 Harriet Hosmer, American neoclassical sculptor, born in Watertown, Massachusetts (d. 1908)
- Oct 10 Isabella II, Queen of Spain (1833-68), born in Madrid, Spain (d. 1904)
- Oct 16 Ferdinand van der Haeghen, Flemish librarian/bibliography
- Oct 24 Belva Ann Lockwood, American attorney (1st lady to argue in Supreme Court), born in Royalton, New York (d. 1917)
- Oct 26 Polibo Fumagalli, Italian composer, born in Inzago, Italy (d. 1900)
- Oct 26 Stephen Elliott, Jr., Brigadier General (Confederate Army), born in Beaufort, South Carolina (d. 1866)
- Oct 30 John S. Bowen, American Major General (Confederate Army), born in Bowen's Creek, Georgia (d. 1863)