Wild Bill Hickok (1837-1876)
May 27 American cowboy and scout, born in Troy Grove, Illinois
- May 27 Ivan Kramskoi, Russian painter and art critic, born in Ostrogozhsk, Voronezh Governorate, Russian Empire (d. 1887)
- May 27 Robert Hoke, American Major General (Confederate Army), born in Lincolnton, North Carolina (d. 1912)
- May 28 George Ashlin, Irish architect noted for his work on churches and cathedrals, born in County Cork, Ireland (d. 1921)
- May 28 Tony Pastor, American vaudeville performer, born in Manhattan, New York (d. 1908)
- May 29 Alexander de Savornin Lohman, Dutch minister and party leader (CHU), born in Groningen, Netherlands (d. 1924)
- May 29 Luca Fumagalli, Italian pianist and composer (Luigi XI), born in Inzago, Lombardo-Venetian Kingdom, Austrian Empire (now Italy) (d. 1908)
- May 31 Ernest Daudet, French journalist and writer (White Terror), born in Nîmes, France (d. 1921)
- May 31 Stephen Dodson Ramseur, American general and the youngest West Pointer to be Major General, born in Lincolnton, North Carolina (d. 1864)
- May 31 William Henry Fitzhugh Lee, American Major General (Confederate Army), born in Arlington House, Virginia (d. 1891)