Constitution Day as well as Citizenship Day is observed every year on September 17th.
September 17 to 23 is officially designated Constitution Week. It is a period of celebration, and appreciation, and allows citizens to learn more about their rights and responsibilities.
It is a federal observance but not a public holiday. Hence businesses stay open as usual. If Constitution Day falls on a Saturday or Sunday, schools, agencies, and other institutions observe it on the next weekday.