Which constitution, signed in 1787, is the oldest written national constitution still in use?

The United States Constitution, signed in 1787, is the oldest written national constitution still in use.

Delegates to the Constitutional Convention in Philadelphia signed the document on 17 September 1787. It established a federal government with separate legislative, executive, and judicial branches and divided powers between the national government and the states. The Constitution took effect after ratification by the required states in 1788.

The document begins with the words “We the People” and contains seven original articles. The first ten amendments, known as the Bill of Rights, were ratified in 1791. Since then, the Constitution has been amended 17 additional times, for a total of 27 amendments.

The phrase “oldest constitution” can be confusing because some countries have older constitutional documents or traditions. The claim here concerns a written national constitution that remains in force. The United States Constitution replaced the Articles of Confederation, the country’s first national governing framework.