- Mar 1 Peter Barlow, English mathematician (b. 1776)
- Mar 2 Frederick West Lander, American Union brigadier general and poet, dies at 40
- Mar 7 Ben McCulloch, US Confederate brigadier general (KIA), dies at 50
- Mar 7 John Baillie McIntosh, US general-major (Union Army), dies at 32
- Mar 7 William Slack, US Confederate brigadier general, dies in battle
- Mar 19 Friedrich Wilhelm von Schadow, German painter (Modern Vasari), dies at 73
- Mar 23 Karl Robert von Nesselrode, German chancellor, dies at 81