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 coat of arms granted to Lawrence Washington (George Washington's 3rd great-grandfather) of Sulgrave Manor Northamptonshire, England, in 1592. This coat of arms was used privately by the president in his home at Mount Vernon.
Text modified from "Flag of Washington, D.C." on Wikipedia which is licensed under CC BY-SA 4.0.