Which document was signed at Independence Hall on September 17, 1787, in the history commemorated by America250?

The United States Constitution was signed at Independence Hall on September 17, 1787.

The signing concluded the Constitutional Convention in Philadelphia, which had met for four months to replace the Articles of Confederation with a stronger federal framework. Thirty-nine delegates endorsed the document, representing 12 states; Rhode Island did not send delegates to the convention.

Independence Hall was then known as the Pennsylvania State House. It had already hosted the debates and signing of the Declaration of Independence in 1776, so the building is associated with both the nation’s independence and its constitutional government.

The Constitution still serves as the supreme law of the United States. The date of its signing is observed annually as Constitution Day and Citizenship Day, although the document did not take effect until the required states ratified it.