On September 17, 1787, state delegates to the Constitutional Convention signed the United States Constitution in Philadelphia, Pennsylvania. On Constitution Day, the 17th of September, the nation remembers this momentous occasion with programs and learning opportunities in schools across the country.
These sites offer a wealth of information on the Constitution, including activities and lesson plans.
https://constitutioncenter.org/learn/hall-pass/constitution-day-2010-the-judicial-branch
The Constitution Annotated provides the section-by-section text of the Constitution along with interpretation of the Constitution over time.
This is a great site for primary sources!
Did you know Constitution Day used to be called Citizenship Day? And before that it was called Proud to be an American Day. Take a look at this citizenship study guide from teh Immigration and Naturalization Service!
Interested in local government? You can fine the text of the California Constitution here.