What was the main purpose of the Declaration of Independence apex? The main purpose of the Declaration of Independence apex was to declare the 13 American colonies as independent states and to dissolve their political connection with Great Britain. Explanation: The Declaration of Independence was adopted by the Continental Congress on July 4, 1776, and is one of the most important documents in American history. Its main purpose was to proclaim the independence of the 13 American colonies from Great Britain, which had been controlling them for decades. The Declaration was written primarily by Thomas Jefferson and also included input from Benjamin Franklin and John Adams. It detailed the reasons why the colonies felt they needed to break away from the British Empire, including grievances against King George III and his policies. The Declaration was a bold statement of freedom and liberty and became a rallying cry for the American Revolution. Today, it remains one of the most significant documents in the history of the United States, and its ideals have inspired people all around the world in their struggle for freedom and democracy.