- Aug 2 John Tyndall, Irish physicist who demonstrated why the sky is blue and proved that the Earth's atmosphere has a greenhouse effect, born in Leighlinbridge, County Carlow, Ireland (d. 1893)
- Aug 3 Luther Orlando Emerson, American composer, born in Parsonsfield, Maine (d. 1915)
- Aug 3 William Miller, American Brigadier General (Confederate Army), born in Ithaca, New York (d. 1909)
- Aug 8 Winfield Scott Featherston "Old Swet", American politician and Army Brigadier General (Confederate), born near Murfreesboro, Tennessee (d. 1891)
- Aug 12 Oliver Mowat, Canadian lawyer and politician (Premier of Ontario 1872-96, a founder of the Canadian Confederation), born in Kingston, Upper Canada (d. 1903) [1]
- Aug 13 George Grove, English biblical scholar and misicographer, born in Clapham, London (d. 1900)
- Aug 13 Joseph Alberdingk Thijm, Dutch poet (Dietsche Warande), born in Amsterdam (d. 1889)
- Aug 16 Andrew Rainsford Wetmore, Canadian politician, born in Fredericton, Canada (d. 1892)
- Aug 20 Adolphe Fétis, Belgian-French pianist and composer, born in Paris (d. 1873)
- Aug 24 Jacopo Tomadini, Italian composer, born in Cividale del Friuli, Italy (d. 1883)
- Aug 26 James Harlan, American politician (Rep-Iowa), US Secretary of Interior (1865-66), born in Clark County, Illinois (d. 1899)
- Aug 30 George Frederick Root, American songwriter (The Battle Cry of Freedom), born in Sheffield, Massachusetts (d. 1895)