The flag of Washington, D.C., consists of three red stars above two red bars on a white background. It is an armorial banner based on the design of the coat of arms of George Washington, first used to identify the family in the 12th century, when one of George Washington's ancestors took possession of Washington Old Hall, County Durham, northeast England. As elements in heraldry, the stars are properly called mullets.
For over a century, the District of Columbia was without an official flag and flew several unofficial banners—usually the flag of the D.C. National Guard. In 1938, Congress established a commission to choose an official, original flag design. The commission held a public competition, and picked the submission of graphic designer Charles A. R. Dunn, who had first proposed his design in 1921.
Dunn's design was officially adopted on October 15, 1938, using the following specification:
The proportions of the design are prescribed in terms of the hoist, or vertical height, of the flag as follows: the upper white portion shall be 3⁄ 10 of the hoist; the two horizontal bars are each 2⁄ 10 of the hoist; the white area between the bars 1⁄ 10 of the hoist; and the base, or lowest white space, is 2⁄ 10 of the hoist. The three five-pointed stars have a diameter of 2⁄ 10 of the hoist and are spaced equidistant in the fly, or horizontal, dimension of the flag. 
In 2002, the D.C. Council debated a proposal to change the flag in protest of the District's lack of voting rights in Congress. The new design would have added the letters "D.C." to the center star and the words " Taxation Without Representation " in white to the two red bars, a slogan already in use on the District's license plates. The change presumably would have been temporary and revoked once the city achieved equal representation or statehood. It passed the council on a 10–2 vote, but support for the proposal soon eroded, and then-mayor Anthony A. Williams never signed the bill. 
In 2001, the flag placed eighth in design quality out of the 72 Canadian provincial, U.S. state, and U.S. territory flags ranked.   In a 2004 poll on the North American Vexillological Association website, Washington, D.C.'s flag was voted the best design among U.S. city flags, just out-polling the flag of Chicago. 
City Council Commemorative Flag Program
Starting on June 1, 2017 the D.C. City Council began a new commemorative flag program    which is similar to the United States Flag program operated by the Congressional Keeper of the Stationery and requested through a constituent's U.S. Senator or U.S. Representative. In the case of the DC Flag interested parties can fill out an online form on the DC Council's website providing a credit card or by sending a letter with applicable check or money order to the Secretary of the City Council requesting a 3x5 or 4x6 District of Columbia flag, once the request is received a flag is taken and then flown on one of several flagpoles at the John A. Wilson Building (the City Council's offices). After the flag has been flown it is then taken and packaged and then sent to the requester with an accompanying certificate that authenticates the flag was flown at the top of a flagpole at the Wilson Building. In its first three months later the D.C. City Council reported that the program was a rousing success filling the council's coffers with additional income.