| 6721 | January 15 | Death | 1781 – Mariana Victoria of Spain (b. 1718) |
| 6722 | January 15 | Death | 1790 – John Landen, English mathematician and theorist (b. 1719) |
| 6723 | January 15 | Death | 1804 – Dru Drury, English entomologist and author (b. 1725) |
| 6724 | January 15 | Death | 1813 – Anton Bernolák, Slovak linguist and priest (b. 1762) |
| 6725 | January 15 | Death | 1815 – Emma, Lady Hamilton, English-French mistress of Horatio Nelson, 1st Viscount Nelson (b. 1761) |
| 6726 | January 15 | Death | 1855 – Henri Braconnot, French chemist and pharmacist (b. 1780) |
| 6727 | January 15 | Death | 1864 – Isaac Nathan, English-Australian composer and journalist (b. 1792) |
| 6728 | January 15 | Death | 1876 – Eliza McCardle Johnson, American wife of Andrew Johnson, 18th First Lady of the United States (b. 1810) |
| 6729 | January 15 | Death | 1885 – Leopold Damrosch, German-American composer and conductor (b. 1832) |
| 6730 | January 15 | Death | 1893 – Fanny Kemble, English-American actress and author (b. 1809) |
| 6731 | January 15 | Death | 1896 – Mathew Brady, American photographer and journalist (b. 1822) |
| 6732 | January 15 | Death | 1909 – Arnold Janssen, German priest and missionary (b. 1837) |
| 6733 | January 15 | Death | 1916 – Modest Ilyich Tchaikovsky, Russian playwright and translator (b. 1850) |
| 6734 | January 15 | Death | 1919 – Karl Liebknecht, German politician (b. 1871) |
| 6735 | January 15 | Death | 1919 – Rosa Luxemburg, German economist, theorist, and philosopher (b. 1871) |
| 6736 | January 15 | Death | 1926 – Enrico Toselli, Italian pianist and composer (b. 1883) |
| 6737 | January 15 | Death | 1929 – George Cope, American painter (b. 1855) |
| 6738 | January 15 | Death | 1936 – Henry Forster, 1st Baron Forster, English cricketer and politician, 7th Governor-General of Australia (b. 1866) |
| 6739 | January 15 | Death | 1937 – Anton Holban, Romanian author, theoretician, and educator (b. 1902) |
| 6740 | January 15 | Death | 1944 – Robert J. Kirby, American police officer (b. 1890) |
| 6741 | January 15 | Death | 1945 – Wilhelm Wirtinger, Austrian-German mathematician and theorist (b. 1865) |
| 6742 | January 15 | Death | 1946 – Karl Nabersberg, German youth leader (b. 1908) |
| 6743 | January 15 | Death | 1948 – Josephus Daniels, American publisher and diplomat, 41st United States Secretary of the Navy (b. 1862) |
| 6744 | January 15 | Death | 1950 – Henry H. Arnold, American general (b. 1886) |
| 6745 | January 15 | Death | 1951 – Nikolai Vekšin, Estonian-Russian captain and sailor (b. 1887) |
| 6746 | January 15 | Death | 1952 – Ned Hanlon, Australian sergeant and politician, 26th Premier of Queensland (b. 1887) |
| 6747 | January 15 | Death | 1955 – Yves Tanguy, French-American painter (b. 1900) |
| 6748 | January 15 | Death | 1964 – Jack Teagarden, American singer-songwriter and trombonist (b. 1905) |
| 6749 | January 15 | Death | 1967 – David Burliuk, Ukrainian author and illustrator (b. 1882) |
| 6750 | January 15 | Death | 1968 – Bill Masterton, Canadian-American ice hockey player (b. 1938) |