What year did the U.S. Constitution go into effect?

The United States Constitution went into effect in 1789. After the Constitutional Convention in 1787, the document was ratified by the necessary nine states by 1788. However, it officially took effect on March 4, 1789, marking the beginning of the new government established under this foundational framework. This particular year is significant as it represents the transition from the Articles of Confederation to a stronger federal government structure, which was outlined in the Constitution. Thus, the year 1789 is integral to understanding the timeline of American governance and the establishment of the Constitution as the supreme law of the land.