Jafferson must have "mislabeled" himself. He professed to being a Deist.
Documentation?
I didn't say he was a Christian
You say you are a Calvinist. I am not. I am of a sect by myself, as far as I know.
-Thomas Jefferson, letter to Ezra Stiles Ely, June 25, 1819
Millions of innocent men, women and children, since the introduction of Christianity, have been burnt, tortured, fined and imprisoned; yet we have not advanced one inch towards uniformity.
-Thomas Jefferson, Notes on Virginia, 1782.
Jefferson believed in what he gathered to be good from his Christian culture and teachings and rejected what he chose from the Bible (to his detriment).
We must reduce our volume to the simple evangelists [and] select, even from them, the very words only of Jesus, paring off the amphibologisms into which they have been led by forgetting often, or not understanding, what had fallen from him.…There will be found remaining the most sublime and benevolent code of morals which has ever been offered to man. I have performed this operation for my own use by cutting verse by verse out of the printed book, and arranging the matter which is evidently his, and which is as easily distinguishable as diamonds in a dunghill. The result is an octavo of forty-six pages of pure and unsophisticated doctrines such as were professed and acted on by the unlettered Apostles, the Apostolic Fathers, and the Christians of the first century. Their Platonizing successors, indeed, in after times, in order to legitimate the corruptions which they had incorporated into the doctrines of Jesus, found it necessary to disavow the primitive Christians, who had taken their principles from the mouth of Jesus himself, of his Apostles, and the Fathers contemporary with them. They excommunicated their followers as heretics.
- To John Adams. Bergh 13:389. (1813.)
[Christ's] system of morality was the most benevolent and sublime probably that has been ever taught, and consequently more perfect than those of any of the ancient philosophers.…[He was] the most innocent, the most benevolent, the most eloquent and sublime character that ever has been exhibited to man. —To Dr. Joseph Priestley. Bergh 10:375. (1803.)
I concur with the author [of a recent sermon] in considering the moral precepts of Jesus as more pure, correct, and sublime than those of the ancient philosophers; yet I do not concur with him in the mode of proving it. He thinks it necessary to libel and decry the doctrines of the philosophers; but a man must be blinded, indeed, by prejudice who can deny them a great degree of merit. I give them their just due, and yet maintain that the morality of Jesus as taught by himself, and freed from the corruptions of latter times, is far superior. Their philosophy went chiefly to the government of our passions, so far as respected ourselves, and the procuring our own tranquility. In our duties to others they were short and deficient. They extended their cares scarcely beyond our kindred and friends individually, and our country in the abstract. Jesus embraced with charity and philanthropy our neighbors, our countrymen, and the whole family of mankind. They confined themselves to actions; he pressed his sentiments into the region of our thoughts, and called for purity at the fountainhead. —Bergh 10:376. (1803.)
[His] system of morals,…if filled up in the style and spirit of the rich fragments he left us, would be the most perfect and sublime that has ever been taught by man.…1. He corrected the deism of the Jews, confirming them in their belief of one only God, and giving them juster notions of His attributes and government. 2. His moral doctrines relating to kindred and friends were more pure and perfect than those of the most correct of the philosophers, and greatly more so than those of the Jews; and they went far beyond both in inculcating universal philanthropy, not only to kindred and friends, to neighbors and countrymen, but to all mankind, gathering all into one family under the bonds of love, charity, peace, common wants, and common aids. A development of this head will evince the peculiar superiority of the system of Jesus over all others. 3. The precepts of philosophy, and of the Hebrew code, laid hold of actions only. He pushed his scrutinies into the heart of man, erected his tribunal in the region of his thoughts, and purified the waters at the fountainhead. 4. He taught emphatically the doctrines of a future state, which was either doubted or disbelieved by the Jews, and wielded it with efficacy as an important incentive, supplementary to the other motives to moral conduct. —To Dr. Benjamin Rush. Bergh 10:384. (1803.)
The doctrines of Jesus are simple, and tend all to the happiness of man:
1. That there is one only God, and He all perfect.
2. That there is a future state of rewards and punishments.
3. That to love God with all thy heart, and thy neighbor as thyself, is the sum of religion.…Had the doctrines of Jesus been preached always as pure as they came from his lips, the whole civilized world would now have been Christian.
—Bergh 15:383. (1822.)
From what I understand, what Jefferson rejected most of all was a material/immaterial duality. This seemed to drive him to refuse the concept of things "supernatural," even when expressed in the Bible he loved, hence his use of "nature and nature's God," the language of at least some Deists, when referring to God.
I think that every Christian sect gives a great handle to atheism by their general dogma that without a revelation there would not be sufficient proof of the being of a God.…On the contrary, I hold (without appeal to revelation) that when we take a view of the universe in its parts, general or particular, it is impossible for the human mind not to perceive and feel a conviction of design, consummate skill, and indefinite power in every atom of its 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 its distribution of lands, waters, and atmosphere; animal and vegetable bodies, examined in all their minutest particles; insects, mere atoms of life, yet as perfectly organized 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 regeneration into new and other forms.
We see, too, evident proofs of the necessity of a superintending power to maintain the universe in its course and order. Stars, well known, have disappeared, new ones have come into view; comets, in their incalculable courses, may run foul of suns and planets, and require renovation under other laws; certain races of animals are become extinct; and were there no restoring power, all existences might extinguish successively, one by one, until all should be reduced to a shapeless chaos.
So irresistible are these evidences of an intelligent and powerful Agent that, of the infinite numbers of men who have existed through all time, they have believed, in the proportion of a million at least to a unit, in the hypothesis of an eternal pre-existence of a Creator, rather than in that of a self-existent universe. Surely this unanimous sentiment renders this more probable than that of the few in the other hypothesis. Some early Christians, indeed, have believed in the co-eternal pre-existence of both the Creator and the world, without changing their relation of cause and effect. —To John Adams. Bergh 15:425. (April 11, 1823.)
I never submitted the whole system of my opinions to the creed of any party of men whatever in religion, in philosophy, in politics, or in anything else where I was capable of thinking for myself. Such an addiction is the last degradation of a free and moral agent.
-letter to Francis Hopkinson, March 13, 1789
While the theological views of Jefferson resemble Deism, Jefferson even refused the creed of Deism, while desiring to cling to Jesus as a moral teacher and effectively a material archetype. One will find Jefferson extolling Jesus Christ, in a very truncated way. I have not found him extolling Deism, per se. This is a real distinction, and as Jefferson himself said, he believed only as he chose, without regard to the tenets of others. But as far as I'm concerned, enough space devoted to Jefferson. (As he stated, when he drafted the Declaration of Independence, he was summing up in his way, the sentiments and positions common to the American people. Naturally, Christians don't object to the idea that God is "nature's God," and they sought agreement with as many fellow revolutionaries as possible.)