In the United States, Flag Day is celebrated on June 14. It commemorates the adoption of the flag of the United States, which happened on that day in 1777 by resolution of the Second Continental Congress. The United States Army also celebrates the Army Birthday on this date; Congress adopted "the American continental army" after reaching a consensus position in the Committee of the Whole on June 14, 1775.
On May 30, 1916, President Woodrow Wilson issued a presidential proclamation establishing a national Flag Day on June 14. Many Americans celebrate Flag Day by displaying the Red, White and Blue in front of homes and businesses. The day commemorates the adoption of the Stars and Stripes as the official flag of the United States.
The week of June 14 is designated as "National Flag Week." During National Flag Week, the president will issue a proclamation urging U.S. citizens to fly the American flag for the duration of that week. The flag should also be displayed on all government buildings. Some organizations hold parades and events in celebration of America’s national flag and everything it represents. Other organizations and tribal groups hold counter-celebrations and protests.
The National Flag Day Foundation holds an annual observance for Flag Day on the second Sunday in June. The program includes a ceremonial raising of the national flag, the recitation of the Pledge of Allegiance, the singing of the national anthem, a parade and other events.
According to American legend, in June 1776, George Washington commissioned Betsy Ross, a Philadelphia seamstress, to create a flag for the new nation in anticipation of a declaration of its independence.
Source: americaslibrary.gov | wikipedia.org