- Sep 1 James Conner, Brigadier General (Confederate Army), (d. 1883)
- Sep 6 Marie Zakrzewska, Polish physician, born in Berlin, Germany (d. 1902)
- Sep 7 August Kekule von Stradonitz, German chemist who discovered structure of benzene ring, born in Darmstadt, Hesse (d. 1896)
- Sep 7 Ferdinand Vandeveer Hayden, American geologist (Geograph Survey 1859-86), born in Westfield, Massachusetts (d. 1887)
- Sep 8 George Crook, American Major General (Union Army), born in Taylorsville, Ohio (d. 1890)
- Sep 8 Seth Barton, American Brigadier General (Confederate Army), born in Fredericksburg, Virginia (d. 1900)
- Sep 12 Anselm Feuerbach, German painter, born in Speyer, Germany (d. 1880)
- Sep 12 Charles Dudley Warner, American novelist (Being a Boy), born in Plainfield, Massachusetts (d. 1900)
- Sep 22 Tự Đức, Emperor of Vietnam (1847-1883) (d. 1883)
- Sep 22 William Worth Belknap, American lawyer and Brevet Major General (Union Army), born in Newburgh, New York (d. 1876)
- Sep 24 Charles S. West, American jurist and politician, born in Camden, South Carolina (d. 1885)
- Sep 24 James St Clair Morton, American engineer, author, and Brigadier General (Union Army), born in Philadelphia, Pennsylvania (d. 1864)
- Sep 25 William Michael Rossetti, English writer and civil servant, born in London, England (d. 1919)
- Sep 29 Bradley Tyler Johnson, Brigadier General (Confederate Army), (d. 1903)
- Sep 29 Giles Alexander Smith, American Major General (Union Army), born in Jefferson County, New York (d. 1876)