The Founding Era in the United States refers to the historical phase that followed independence from Britain in the late 18th century, during which the constitutional and political foundations of the new republic were established. Its core lies in the drafting of the 1787 Constitution, which became the supreme reference document that enshrined the principles of liberty, federalism, and the separation of powers, thereby forming the social contract of the American state. This period is closely associated with the Founding Fathers, and is therefore also known as the Founding Period or the First Constitutional Era, and is sometimes referred to as the Early Republic. In other words, it represents a foundational moment in redefining political legitimacy and shaping national identity, making it a comparative model for modern state-building experiences worldwide.