- Aug 10 Nathaniel Lyon, American Brigadier-General (Union Army), 1st Union General to die in battle at 43
- Aug 12 Eliphalet Remington, American firearms manufacturer (Remington Arms Co., L.L.C.), dies at 67
- Aug 17 Alcée Louis la Branche, American Politician (b. 1806)
- Aug 22 Xianfeng, Emperor of the Manchu-led Qing dynasty, dies at 30
- Aug 29 Franz Joseph Glæser, Czech-Danish composer, dies at 63