- May 4 Joseph Whitaker, British publisher (Whitaker's Almanack), born in London (d. 1895)
- May 4 Julia Gardiner Tyler, 2nd wife of President John Tyler (1841-45), born in Gardiners Island, New York (d. 1889)
Florence Nightingale (1820-1910)
May 12 British nurse who revolutionized nursing during the Crimean War, born in Florence, Grand Duchy of Tuscany (now Italy)
- May 22 Alexander Fesca, German pianist and composer (Piano Septets), born in Karlsruhe, Germany (d. 1849)
- May 23 James Buchanan Eads, American engineer and inventor (Eads Bridge-St Louis), born in Lawrenceburg, Indiana (d. 1887)
- May 23 Lorenzo Sawyer, 9th Chief Justice of the Supreme Court of California, born in Le Roy, New York (d. 1891)
- May 27 Mathilde Bonaparte, French princess (daughter of Napoleon's brother Jérôme Bonaparte and his second wife, Catharina of Württemberg, daughter of King Frederick I of Württemberg) and socialite, born in Trieste, Austrian Empire (d. 1904)
- May 28 Willem Doorenbos, Dutch literary and critic, born in Deersum, Netherlands (d. 1906)
- May 30 Pierre-Joseph-Olivier Chauveau, French Canadian politician (1st Premier of Quebec), born in Charlesbourg, Quebec (d. 1890)
20-29
30-39
40-49
50-59
80-89
Over 90