Flagg is an unincorporated community in the southeastern portion of Ogle County in Flagg Township, Illinois, United States.

It may be found at the crossroads of Grange and Titus Roads.

[3] The Flagg post office was discontinued in 1917.

[4] In 1936, the Galena and Chicago Union Railroad had a station in Flagg.

This Ogle County, Illinois location article is a stub.