Final answer:
Three key Founding Fathers are George Washington, commander-in-chief of the Continental Army and first President; Thomas Jefferson, principal author of the Declaration of Independence and third President; and James Madison, influential in drafting the Constitution and Bill of Rights, also worked on The Federalist Papers.
Step-by-step explanation:
Three Founding Fathers who played critical roles in the establishment of the United States of America are George Washington, Thomas Jefferson, and James Madison.
George Washington, known as the Father of His Country, served as the commander-in-chief of the Continental Army during the American Revolutionary War and later became the first President of the United States. His leadership was instrumental in achieving American independence and setting the nation on its founding principles.
Thomas Jefferson was the principal author of the Declaration of Independence, through which the Thirteen Colonies officially broke political ties with Great Britain. Jefferson later served as the third President of the United States, promoting the expansion of the country through the Louisiana Purchase.
James Madison, often referred to as the "Father of the Constitution," played a significant role at the Constitutional Convention and crafted the framework for the Constitution and the Bill of Rights. Along with Alexander Hamilton and John Jay, Madison authored The Federalist Papers, elucidating and defending the proposed constitution to the public.