The history of Flag Day 2021 dates back to June 14, 1777, when British symbols of the Grand Union flag were replaced with a new design featuring 13 white stars in a circle on a field of blue and 13 red and white stripes ( one for each state) by the Continental Congress. The number of stars increased as the new states entered the Union, but the number of stripes stopped at 15 and was later returned to 13.

In June 1886 Bernard Cigrand made his first public proposal for the annual observance of the birth of the flag. Cigrand's efforts to ensure national observance of Flag Day finally came when President Woodrow Wilson issued a proclamation calling for a nationwide observance of the event on June 14, 1916.

However, Flag Day did not become official until August 1949, when President Harry Truman signed the legislation and proclaimed June 14 as Flag Day. In 1966, Congress also requested that the President issue annually a proclamation designating the week in which June 14 occurs as National Flag Week.v