1. The Pentagon, located in Arlington, Virginia, near Washington D.C., was one of the targets of the September 11 attacks. Flight 77, hijacked by terrorists, crashed into the west side of the building, causing significant damage and loss of life.

2. The District Of Columbia was declared a federal disaster area due to the attacks, allowing for federal aid to help with recovery efforts.

3. The attacks caused the closure of all federal government buildings in the District Of Columbia, including the White House and the U.S. Capitol. This was the first time in history that the Capitol had been evacuated due to a security threat.

4. Many District Of Columbia residents and officials were involved in the response and recovery efforts after the attacks. Members of the D.C. Fire and EMS Department, as well as local hospitals and medical centers, provided aid to those injured in the attacks.

5. The National September 11 Memorial & Museum, located in New York City, features a section dedicated to the victims of the attacks who had ties to the District Of Columbia. The section includes artifacts and personal stories from the victims and their families.