The religious views of Thomas Jefferson diverged widely from the traditional Christianity of his era. Throughout his life, Jefferson was intensely interested in theology, religious studies, and morality.Ahlstrom p. 366Charles Sanford, The Religious Life of Thomas Jefferson (Charlotte: UNC Press, 1987). Jefferson was most comfortable with Deism, rational religion, theistic rationalism, and Unitarianism.Michael Corbett and Julia Mitchell Corbett, Politics and religion in the United States (1999) p. 68 He was sympathetic to and in general agreement with the moral precepts of Christianity.Scherr, Arthur. Thomas Jefferson Versus the Historians: Christianity, Atheistic Morality, and the Afterlife. Cambridge University Press. 2016 He considered the teachings of Jesus as having "the most sublime and benevolent code of morals which has ever been offered to man,"Jefferson, Washington, 1907, p. 89 yet he held that the pure teachings of Jesus appeared to have been appropriated by some of Jesus' early followers, resulting in a Bible that contained both "diamonds" of wisdom and the "dung" of ancient political agendas.Thomas Jefferson and his Bible April, 1998, PBS Frontline, downloaded 15-04-03

Jefferson held that "acknowledging and adoring an overruling providence" (as in his First Inaugural AddressThomas Jefferson, First Inaugural Address) was important and in his second inaugural address, expressed the need to gain "the favor of that Being in whose hands we are, who led our fathers, as Israel of old".Thomas Jefferson, Second Inaugural Address, Monday, March 4, 1805 Still, together with James Madison, Jefferson carried on a long and successful campaign against state financial support of churches in Virginia. Jefferson also coined the phrase "wall of separation between church and state" in his 1802 letter to the Danbury Baptists of Connecticut. During his 1800 campaign for the presidency, Jefferson even had to contend with critics who argued that he was unfit to hold office because of their discomfort with his "unorthodox" religious beliefs.

Jefferson used certain passages of the New Testament to compose The Life and Morals of Jesus of Nazareth (the "Jefferson Bible"), which excluded any miracles by Jesus and stressed his moral message. Though he often expressed his opposition to many practices of the clergy, and to many specific popular Christian doctrines of his day, Jefferson repeatedly expressed his admiration for Jesus as a moral teacher, and consistently referred to himself as a Christian (though following his own unique type of Christianity) throughout his life. Jefferson opposed Calvinism, Trinitarianism, and what he identified as Platonic elements in Christianity. He admired the religious work of Joseph Priestley (an English chemist and theologian who moved to America). In private letters Jefferson also described himself as subscribing to other certain philosophies, in addition to being a Christian. In these letters he described himself as also being an "Epicurean" (1819), a "19th century materialist" (1820), a "Unitarian by myself" (1825), and "a sect by myself" (1819).

When John Adams and Jefferson resumed their correspondence between 1812 and 1826, religion was among the topics discussed. As an octogenarian, Jefferson transcribed his religious view thusly:When we take a view of the Universe, in parts general or particular, it is impossible for the human mind not to and feel a conviction of design, consummate skill, and indefinite power in every atom of composition. the movements of the heavenly bodies, so exactly held in their course by the balance of centrifugal and centripetal forces, the structure of our earth itself, with distribution of lands, waters and atmosphere, animal and vegetable bodies, examined in all their minutest particles, insects mere atoms of life, yet as perfectly organised as man or mammoth, the mineral substances, their generation and uses, it is impossible, I say, for the human mind not to believe that there is, in all this, design, cause and effect, up to an ultimate cause, a fabricator of all things from matter and motion, their preserver and regulator while permitted to exist in their present forms, and their regenerator into new and other forms.

Church attendance Jefferson was raised in the Church of England at a time when it was the established church in Virginia and the only denomination funded by Virginia tax money. Before the Revolution, parishes were units of local government, and Jefferson served as a vestryman, a lay administrative position in his local parish. Office-holding qualifications at all levels—including the Virginia House of Burgesses, to which Jefferson was elected in 1769—required affiliation with the current state religion and a commitment that one would neither express dissent nor do anything that did not conform to church doctrine. Jefferson counted clergy among his friends, and he contributed financially to the Anglican Church he attended regularly.

Following the Revolution, the Church of England in America was disestablished. It reorganized as the Episcopal Church in America. Margaret Bayard Smith, whose husband was a close friend of Jefferson, records that during the first year of Jefferson's presidency he "regularly attended service on" Sunday in a small Catholic chapel, out of respect for public worship.Smith, Margaret Bayard. "The first forty years of Washington society, portrayed by the family letters of Mrs. Samuel Harrison Smith (Margaret Bayard) from the collection of her grandson, J. Henley Smith." Internet Archive. 5 October 2016. p.13 This was the only church in the new city, with the exception of a little Episcopal church. Within a year of his inauguration, Jefferson began attending church services in the House of Representatives, a custom which had not yet begun while he was vice president, and which featured preachers of every Christian sect and denomination.

Henry S. Randall, the only biographer permitted to interview Jefferson's immediate family, recorded that Jefferson "attended church with as much regularity as most of the members of the congregation—sometimes going alone on horse-back, when his family remained at home", and that he also "contributed freely to the erection of Christian churches, gave money to Bible societies and other religious objects, and was a liberal and regular contributor to the support of the clergy. Letters of his are extant which show him urging, with respectful delicacy, the acceptance of extra and unsolicited contributions, on the pastor of his parish, on occasions of extra expense to the latter, such as the building of a house."Henry S. Randall, The life of Thomas Jefferson, p. 555

In later years, Jefferson refused to serve as a godparent for infants being baptized, because he did not believe in the dogma of the Trinity. Despite testimony of Jefferson's church attendance, there is no evidence that he was ever confirmed or was a communicant.

Deism

In 1760, at age 16, Jefferson entered the College of William & Mary in Williamsburg, and for two years he studied mathematics, metaphysics, and philosophy under Professor William Small. He introduced the enthusiastic Jefferson to the writings of the British Empiricists, including John Locke, Francis Bacon, and Isaac Newton.Merrill D. Peterson, ed. Thomas Jefferson: Writings, p. 1236 Jefferson biographers say that he was influenced by deist philosophy while at William & Mary, particularly by Bolingbroke.

Phrases such as "Nature's God", which Jefferson used in the Declaration of Independence, are typical of Deism, although they were also used at the time by non-Deist thinkers, such as Francis Hutcheson. In addition, it was part of Roman thinking about natural law, and Jefferson was influenced by reading Cicero on this topic.Jefferson's Literary Commonplace Book, trans. and ed. Douglas L. Wilson (Princeton, N.J.: Princeton University Press, 1989), p. 159.

Most deists denied the Christian concepts of miracles and the Trinity. Though he had a lifelong esteem for Jesus' moral teachings, Jefferson did not believe in miracles, nor in the divinity of Jesus. In a letter to deRieux in 1788, he declined a request to act as a godfather, saying he had been unable to accept the doctrine of the Trinity "from a very early part of my life". (letter to J.P.P Derieux, July 25, 1788, Papers vol. 13, p. 418) In an 1820 letter to his close friend William Short, Jefferson stated, "it is not to be understood that I am with him [Jesus] in all his doctrines. I am a Materialist; he takes the side of Spiritualism; he preaches the efficacy of repentance toward forgiveness of sin; I require a counterpoise of good works to redeem it.""The character of Thomas Jefferson: as exhibited in his own writings" By Theodore Dwight, p. 363 In 1824, four years later, Jefferson had changed on his view of the "materialism" of Jesus, clarifying then that "... the founder of our religion, was unquestionably a materialist as to man.""The Battle for the American Mind: A Brief History of a Nation's Thought" By Carl J. Richard, p. 98"From Thomas Jefferson to Augustus Elias Brevoort Woodward, 24 March 1824," Founders Online, National Archives, accessed September 29, 2019. [This is an Early Access document from The Papers of Thomas Jefferson: Retirement Series. It is not an authoritative final version.]. Internet Archive capture from 2020-01-02.

Jefferson was directly linked to deism in the writings of some of his contemporaries. Patrick Henry's widow wrote in 1799, "I wish the Grate Jefferson & all the Heroes of the Deistical party could have seen my ... Husband pay his last debt to nature." Avery Dulles, a leading Catholic theologian, states that while at the College of William & Mary, "under the influence of several professors, he [Jefferson] converted to the deist philosophy". Dulles concludes:

Dulles concurs with historian Stephen Webb, who states that Jefferson's frequent references to "Providence" indicate his Deism, as "most eighteenth-century deists believed in providence".Stephen H. Webb, American providence: a nation with a mission (2004) p. 35

While many biographers, as well as some of his contemporaries, have characterized Jefferson as a Deist, historians and scholars have not found any such self-identification in Jefferson's surviving writings. In an 1803 letter to Priestley, Jefferson praises Jesus for a form of deism. He expressed similar ideas in an 1817 letter to John Adams.

In a letter to Adams dated August 22, 1813, Jefferson wrote that:

Disestablishment of religion in Virginia

For Jefferson, separation of church and state was a necessary reform of the religious tyranny whereby a religion received state endorsement, and those not of that religion were denied rights, and even punished.

Following the Revolution, Jefferson played a leading role in the disestablishment of religion in Virginia. Previously as the established state church, the Anglican Church received tax support and no one could hold office who was not an Anglican. The Presbyterian, Baptist and Methodist churches did not receive tax support. As Jefferson wrote in his Notes on Virginia, pre-Revolutionary colonial law held that "if a person brought up a Christian denies the being of a God, or the Trinity ... he is punishable on the first offense by incapacity to hold any office."Jefferson, Thomas. "Notes on the State of Virginia." Google Books. 26 May 2017.