Patriot Day is a United States national observance that honors the memory of those who were killed in the September 11 attacks. It was first observed in 2002, after the proclamation by President George W. Bush.
On September 11, 2001 al-Qaeda launched a series of coordinated terrorist attacks upon the United States, killing almost 3,000 people. In the immediate aftermath of the tragic events, President proclaimed September 14, 2001 as a National Day of Prayer and Remembrance for the Victims of the Terrorist Attacks on September 11, 2001. A year later, September 11 was made a national day of mourning referred to as Patriot Day. This observance has been proclaimed annually since 2002.
In 2009, President Barack Obama rededicated it as Patriot Day and National Day of Service and Remembrance. It is not a public holiday therefore government offices, educational institutions and businesses do not close on this day. On Patriot Day, the national flag is flown at half-mast on all United States government buildings and establishments. Individuals are also encouraged to display flags on their homes.