The official flag of Chicago is highly symbolic like the flag of the U.S itself and is considered to be one of the landmark flags in America. Of all the cities in the U.S, it has got the second highest ranks in terms of value and symbolism only after the flag of Washington DC.

At the onset, the flag may appear to be very simple. It has two blue and three white horizontal stripes as well as four red stars in the middle of the white stripe. However, underneath, the flag represents a rich socio-political history of the region.

About the flag of Chicago

http://en.wikipedia.org/wiki/Flag_of_Chicago

The three white lines represent the directions of the city, namely north, west and south. The blue lines are the two tributaries of the Chicago River. There are also four red stars that symbolize the four significant events in the history of Chicago.

The first one symbolizes the Fort Dearborn. The second star stands for the Chicago Fire that took place in the October of 1871. The third star embodies the famous Columbian Exposition of the late 19th century. The last one, added in the mid-20th century, signifies the Century of Development.

symbolism and history of Chicago flag

http://www.chicagohistoryjournal.com/2008/05/long-may-she-wave-flag-of-chicago.html

Further reading of Chicago flag

http://www.chicagopostcardmuseum.org/meaning_of_the_chicago_flag.html

The Chicago flag became official on April 4, 1917. In 1915, W.H. Thompson, the then city mayor, appointed a commission of intellectuals from different walks of life to formulate a suitable flag design that represents the rich history of the city. The committee received thousands of entries. Finally, the design by renowned poet Wallace Rice was selected as the best design and got approved by the committee.

Origin of Chicago flag

http://flags.wikia.com/wiki/Chicago_%281917-1933%29