Yes, September 11 is officially designated as Patriot Day in the United States. It is a national day of observance to remember and honor the thousands of individuals who were killed in the terrorist attacks of September 11, 2001. The day is also known as the National Day of Service and Remembrance.
Following the attacks, U.S. President George W. Bush signed into law a joint resolution by Congress (Public Law 107-89) on December 18, 2001, which designated September 11 of each year as Patriot Day. The proclamation directs that the flag of the United States be flown at half-staff at all U.S. government buildings and establishments, both at home and abroad. It also calls for Americans to observe a moment of silence at 8:46 a.m. (Eastern Daylight Time), the time the first plane struck the North Tower of the World Trade Center. This day should not be confused with Patriots' Day, an official holiday in Massachusetts and Maine commemorating the battles of Lexington and Concord in April.
While it is a national observance, Patriot Day is not a federal holiday, meaning schools and businesses do not typically close. Its primary purpose is to serve as a day of solemn reflection. In 2009, Congress further designated September 11 as a National Day of Service and Remembrance, encouraging Americans to engage in charitable service and community activities as a tribute to the victims, survivors, and first responders of the 9/11 attacks.