Constitution Day and Citizenship Day (observed 16 Sept); US Constitution Week (17-23 Sept) and National POW/MIA Recognition Day

Constitution Day and Citizenship Day on September 17 commemorates the formation and signing of the Constitution of the United States on September 17, 1787. It is dedicated to all US citizens.
Constitution Day will be observed on Friday September 16, 2016
http://constitutioncenter.org/learn/civic-calendar/constitution-day-civic-holiday
And

National POW/MIA Recognition Day will be observed on Friday, Sept. 16, 2016.

www.pow-miafamilies.org/events/recognition-day