John Oliver Duer
- Born February 12, 1838, Baltimore, Maryland; moved to Galena in 1860 at the age of 22
- Commissioned 2nd Lieutenant Company D, 45th Illinois Infantry, September 1861; promoted 1st Lieutenant, March 1862
- Promoted Captain, April 1862; promoted Major, June 1863; promoted Lieutenant Colonel, January 1865; promoted Colonel, May 1865
- Promoted brevet Brigadier General, for war service, July 12, 1865; mustered out the same day
- Removed to Monticello, Iowa, as head of dry goods firm of Duer & Estey; elected mayor of Monticello; died 1880; buried in Monticello, Iowa