Flagg is an unincorporated community in the southeastern portion of Ogle County in Flagg Township. It may be found at the crossroads of Grange and Titus Roads.
Flagg took its name from its location in Flagg Township. The Flagg post office was discontinued in 1917.
- ^ U.S. Geological Survey Geographic Names Information System: Flagg
- ^ "Location of Flagg, Illinois". MapQuest. Retrieved 16 June 2010.
- ^ Chicago and North Western Railway Company (1908). A History of the Origin of the Place Names Connected with the Chicago & North Western and Chicago, St. Paul, Minneapolis & Omaha Railways. p. 71.
- ^ "Ogle County". Jim Forte Postal History. Retrieved 17 March 2015.