- May 6 Martin Delany, African-American abolitionist and physician (1st African American major in US Army), born in Charles Town, Virginia (d. 1885)
- May 12 Edward Lear, English landscape painter and poet (Complete Nonsense Book), born in London, England (d. 1888)
- May 12 Louis Ludwig Blenker, German-American Brigadier General (Union Army), born in Worms, Germany (d. 1863)
- May 14 Emilie Mayer, German composer of Romantic music, born in Friedland, Mecklenburg-Vorpommern, Swedish Pomerania (now Germany) (d. 1883)
- May 17 Joseph Warren Revere, American Brigadier General (Union Army), born in Boston, Massachusetts (d. 1880)
- May 19 Felix Zollicoffer, American journalist and Confederate Brigadier General who was killed in the Battle of Mill Springs, born in Maury County, Tennessee (d. 1862)
- May 20 Gustav Mankell, Moravian-Swedish organist and composer, born in Christiansfeld, Denmark (d. 1880)
- May 23 Henri-François-Alphonse Esquiros, French poet and writer (Les Vierges Folles), born in Paris (d. 1876)
- May 30 John Alexander McClernand, American politician and Major General (Union Army), born in Breckinridge County, Kentucky (d. 1900)
20-29
30-39
40-49
50-59
80-89
Over 90