+.The Declaration of Independence: One of the most important historical documents of the U.S. written by Thomas Jefferson and adopted by the Second Continental Congress in Philadelphia on July 4, 1776. It declared formally the independence of the thirteen colonies in North America from Great Britain .The Declaration of Independence: One of the most important historical documents of the U.S. written by Thomas Jefferson and adopted by the Second Continental Congress in Philadelphia on July 4, 1776. It declared formally the independence of the thirteen colonies in North America from Great Britain