| 70801 | June 21 | Birth | 1759 – Alexander J. Dallas, American lawyer and politician, 6th United States Secretary of the Treasury (d. 1817) |
| 70802 | June 21 | Birth | 1763 – Pierre Paul Royer-Collard, French philosopher and academic (d. 1845) |
| 70803 | June 21 | Birth | 1764 – Sidney Smith, English admiral and politician (d. 1840) |
| 70804 | June 21 | Birth | 1774 – Daniel D. Tompkins, American lawyer and politician, 6th Vice President of the United States (d. 1825) |
| 70805 | June 21 | Birth | 1781 – Siméon Denis Poisson, French mathematician and physicist (d. 1840) |
| 70806 | June 21 | Birth | 1786 – Charles Edward Horn, English singer-songwriter (d. 1849) |
| 70807 | June 21 | Birth | 1788 – Princess Augusta of Bavaria (d. 1850) |
| 70808 | June 21 | Birth | 1791 – Robert Napier, Scottish engineer and educator (d. 1876) |
| 70809 | June 21 | Birth | 1792 – Ferdinand Christian Baur, German theologian and scholar (d. 1860) |
| 70810 | June 21 | Birth | 1797 – Wilhelm Küchelbecker, Russian poet and author (d. 1846) |
| 70811 | June 21 | Birth | 1805 – Charles Thomas Jackson, American physician and geologist (d. 1880) |
| 70812 | June 21 | Birth | 1811 – Carlo Matteucci, Italian physicist and neurophysiologist (d. 1868) |
| 70813 | June 21 | Birth | 1814 – Anton Nuhn, German anatomist and academic (d. 1889) |
| 70814 | June 21 | Birth | 1823 – Jean Chacornac, French astronomer (d. 1873) |
| 70815 | June 21 | Birth | 1825 – Thomas Edward Cliffe Leslie, Irish economist and jurist (d. 1882) |
| 70816 | June 21 | Birth | 1825 – William Stubbs, English bishop and historian (d. 1901) |
| 70817 | June 21 | Birth | 1828 – Ferdinand André Fouqué, French geologist and academic (d. 1904) |
| 70818 | June 21 | Birth | 1834 – Frans de Cort, Flemish poet and author (d. 1878) |
| 70819 | June 21 | Birth | 1834 – Elizabeth Jane Caulfeild, Countess of Charlemont (d. 1882) |
| 70820 | June 21 | Birth | 1839 – Joaquim Maria Machado de Assis, Brazilian author, poet, and playwright (d. 1908) |
| 70821 | June 21 | Birth | 1845 – Arthur Cowper Ranyard, English astrophysicist and astronomer (d. 1894) |
| 70822 | June 21 | Birth | 1846 – Marion Adams-Acton, Scottish-English author and playwright (d. 1928) |
| 70823 | June 21 | Birth | 1850 – Daniel Carter Beard, American author and illustrator, co-founded the Boy Scouts of America (d. 1941) |
| 70824 | June 21 | Birth | 1850 – Enrico Cecchetti, Italian ballet dancer (d. 1928) |
| 70825 | June 21 | Birth | 1857 – Hugh Newall, English astrophysicist and academic (d. 1944) |
| 70826 | June 21 | Birth | 1858 – Medardo Rosso, Italian sculptor and educator (d. 1928) |
| 70827 | June 21 | Birth | 1859 – Henry Ossawa Tanner, American-French painter and illustrator (d. 1937) |
| 70828 | June 21 | Birth | 1862 – Damrong Rajanubhab, Thai historian and author (d. 1943) |
| 70829 | June 21 | Birth | 1863 – Max Wolf, German astronomer and academic (d. 1932) |
| 70830 | June 21 | Birth | 1864 – Heinrich Wölfflin, Swiss historian and critic (d. 1945) |