Religion: Deist (although he has long been considered a deist, Thomas Jefferson has been known to hold multiple religious views)

During the presidential campaign of 1800, the Federalists attacked Jefferson as an infidel, claiming that Jefferson's intoxication with the religious and political extremism of the French Revolution disqualified him from public office. But Jefferson wrote at length on religion and many scholars agree with the claim that Jefferson was a deist, a common position held by intellectuals in the late 18th century, at least for much of his life. As Avery Dulles, a leading Catholic theologian reports, "In his college years at William and Mary [Jefferson] came to admire Francis Bacon, Isaac Newton, and John Locke as three great paragons of wisdom. Under the influence of several professors he converted to the deist philosophy."[42].

Jefferson used deist terminology in repeatedly stating his belief in a creator, and in the United States Declaration of Independence used the terms "Creator" and "Nature's God." Jefferson believed, furthermore, it was this Creator that endowed humanity with a number of inalienable rights, such as "life, liberty, and the pursuit of happiness."

Founding Fathers who were especially noted for being influenced by such philosophy include Thomas Jefferson, Benjamin Franklin, Cornelius Harnett, Gouverneur Morris, and Hugh Williamson. Although these men were members of traditional Christian denominations (Hugh Williamson and Benjamin Franklin were Presbyterians and the rest were Episcopalians), their political speeches show distinct deistic influence. Other notable Founding Fathers may have been more directly deist. These include James Madison, John Adams, possibly Alexander Hamilton, Ethan Allen[32] and Thomas Paine (who published The Age of Reason, a treatise that helped to popularize deism throughout America and Europe).

Further, Jefferson specifically named Joseph Priestly (English Unitarian who moved to America) and Conyers Middleton (English Deist) and said: "I rest on them ... as the basis of my own faith" (letter to Adams, Aug. 22, 1813). Therefore, without using the actual words, Jefferson issued an authentic statement claiming Deism as his faith.