- Aug 5 Griffin A Stedman, American Brigadier General (Union Army), dies in battle at 26
- Aug 7 Li Xiucheng, late Taiping's Field Marshal and soul person.(b. 1823)
- Aug 12 Sakuma ShÅzan, Japanese reformer (b. 1811)
- Aug 15 Daniel Phineas Woodbury, US engineer/Union general-major, dies
- Aug 16 John Randolph Chambliss Jr, American Brigadier-General (Confederate Army), dies in battle at 31
- Aug 20 Daniel Chaplin, US Union brigadier general, dies
- Aug 20 John H Kelly, US Confederate brigadier general, dies in battle at 24
- Aug 21 John Calhoun Sanders, Confederate brigadier general, dies in battle at 24
- Aug 31 Ferdinand Lassalle, French socialist and political activist (Allgemeiner), dies at 39