This is about the film. For the stage musical on which it is based, see 1776 (musical).
- William Daniels - John Adams
- Howard Da Silva - Benjamin Franklin
- Ken Howard - Thomas Jefferson
- Donald Madden - John Dickinson
- John Cullum - Edward Rutledge
- David Ford - John Hancock
- Ronald Holgate - Richard Henry Lee
- Blythe Danner - Martha Jefferson
- Virginia Vestoff - Abigail Adams
- Ralston Hill - Charles Thomson
- William Duell - Andrew McNair
- Stephen Nathan - Courier
- John Myhers - Robert Livingston
- Rex Robbins - Roger Sherman
- Mark Montgomery - Leather Apron
While General George Washington is conducting the struggle against the British Empire on the battlefield, the Continental Congress in Philadelphia piddles away its time over trivial matters and continually refuses to begin debating the question of American independence. The leader of the independence faction is the abrasive John Adams of Massachusetts, whose continuous pushing of the issue has brought their cause to a complete standstill. John Dickinson of Pennsylvania leads the opposition that hopes for reconciliation with England. During his quieter moments, Adams calls up the image of his wife Abigail Adams who resides in Massachusetts and gives him insight and encouragement. Dr. Benjamin Franklin of Pennsylvania suggests another colony that supports independence should submit a proposal.
Richard Henry Lee of Virginia voluntarily rides off to Williamsburg, Virginia to get authorization from the Virginia Colony to propose independence. Dr. Lyman Hall arrives to represent Georgia, and immediately, he is interrogated by his fellow delegates regarding his views on independence (with Dickinson framing it as "treason"). Weeks later, Lee returns with the resolution, and debate on the question begins. However, in the midst of debate, Caesar Rodney falters because of his cancer and is taken back to Delaware by fellow delegate Thomas McKean, leaving the anti-independence George Read to represent Delaware.
After heated discussions, the question is called without a majority of positive votes present. The New Jersey delegation, led by Reverend John Witherspoon, arrives just in time to provide a vote supporting independence. In a move intended to defeat the resolution, Dickinson calls for a vote requiring unanimity for passage. The vote ends in a tie between the colonies, New York abstaining as it does in every vote. It is ultimately decided in favor of unanimity by John Hancock, president of the Continental Congress, who argues that any objecting colony would fight for England against independence. Stalling for time to rally support for the resolution, Adams and Franklin call again for a postponement, justifying their call by stating the need for a declaration describing their grievances. Once again tied and ultimately decided by Hancock, the vote is successfully postponed until such a document can be written.
Hancock appoints a committee that includes Adams, Franklin, Roger Sherman of Connecticut, Robert Livingston of New York, and Thomas Jefferson (after Lee declines due to an appointment to serve as governor of Virginia). Jefferson resists because he desires to return home to Virginia to see his wife, Martha, but the others present more compelling reasons to avoid the responsibility; they opine that Jefferson's diplomatic nature and superior writing skill are required to draft the declaration. Jefferson develops writer's block due to missing his wife, so Adams sends for Martha: "It simply occurred to me that the sooner his problem was solved the sooner ours would be." Upon meeting her, Adams and Franklin are quite taken with Martha. While maneuvering to get the required unanimity for the vote on independence, Adams, Franklin and Samuel Chase of Maryland visit the Colonial Army encamped in New Brunswick, New Jersey, at the request of General Washington, to help convince Maryland.
When they return to Philadelphia, the declaration is read and then subsequently debated and amended. Jefferson agrees to most alterations to the document, much to Adams' growing consternation. The debate reaches a head when the Southern delegates, led by Edward Rutledge of South Carolina, walk out of Congress when a clause opposing slavery is not removed. Adams remains adamant that the clause remain, but Franklin appeals to him to allow the passage to be removed so that they can first achieve the vote on independence and the formation of a nation, deferring the slavery fight to a later time. Adams leaves the final decision to Jefferson, who reluctantly concedes. After removing that clause, 11 of 13 colonies are now in favor. New York abstains yet again (since its delegates have never been given specific orders by the disorganized New York legislature).
The question is therefore up to the Colony of Pennsylvania, whose delegation is polled at Franklin's request. Franklin votes for the declaration, but Dickinson votes against. The outcome is now in the hands of their fellow Pennsylvanian Judge James Wilson. Wilson has always followed Dickinson's lead, but in this case Wilson votes in favor of the declaration, securing its passage, so that he would not be remembered by history as the man who voted to prevent American independence. After receiving word of the destruction of his property from General Washington, Lewis Morris finally withdraws New York's abstention and agrees to sign the document. Finally, with the Declaration of Independence ready to be signed, Hancock places his signature first, whereupon the others (including New York) affix theirs to the Declaration, establishing the United States on July 4, 1776.
- "Sit Down, John" - John Adams and Congress
- "Piddle, Twiddle and Resolve" - John Adams
- "Till Then" - Abigail and John Adams
- "The Lees of Old Virginia" - Lee, Franklin and John Adams
- "But, Mr. Adams" - John Adams, Franklin, Sherman, Livingston and Jefferson
- "Yours, Yours, Yours" - Abigail and John Adams
- "He Plays the Violin" - Martha, Jefferson and John Adams
- "Cool, Cool, Considerate Men" - Dickinson, Rutledge, Hancock and Congress
- "Momma Look Sharp" - Courier, McNair and Leather Apron
- "The Egg" - Franklin, John Adams and Jefferson
- "Molasses to Rum" - Rutledge
- "Is Anybody There?" - John Adams
- "Finale" - Thomson and Congress