- Oct 2 Edmund Jackson Davis, American lawyer, soldier, and Brigadier General (Union Army), born in St. Augustine, Florida (d. 1883)
- Oct 6 Cark Reidel, German composer and conductor, born in Cronenberg, Wuppertal (d. 1888)
- Oct 14 James Sidney Robinson, American politician and Brevet Major General (Union Army), born in Mansfield, Ohio (d. 1892)
- Oct 14 William Harcourt, British Home Secretary and Chancellor of the Exchequer, born in York, England (d. 1904)
- Oct 21 Peter Paul Maria Alberdingk Thijm, Dutch historian and writer, born in Amsterdam, Netherlands (d. 1904)
- Oct 29 Marcellin Berthelot, French chemist (Thomsen–Berthelot principle of thermochemistry), born in Paris (d. 1907)
- Oct 31 Richard Morris Hunt, American architect and educator, born in Brattleboro, Vermont (d. 1895)