Several Founding Fathers of the United States held views that diverged from traditional Christian orthodoxy, including skepticism or rejection of the doctrine of the Trinity (the belief in God as three persons: Father, Son, and Holy Spirit). Based on historical records, the following key figures are noted for their non-Trinitarian or unorthodox religious beliefs:

• Thomas Jefferson: Jefferson, a key author of the Declaration of Independence, explicitly rejected the Trinity. He was a Deist with Unitarian leanings, believing in a single, rational God and dismissing Trinitarian theology as illogical. In his writings, such as letters to John Adams and others, he criticized the concept of the Trinity as a corruption of Jesus’ teachings, favoring a view of Jesus as a moral teacher rather than a divine figure.
• John Adams: Adams, the second U.S. President, also leaned toward Unitarianism later in life. While raised in a Congregationalist background, his correspondence (especially with Jefferson) reveals skepticism about the Trinity, viewing it as a theological construct not grounded in reason or scripture. He emphasized a singular God and saw Trinitarian doctrine as overly dogmatic.
• Benjamin Franklin: Franklin, a Deist, was skeptical of organized religion and traditional Christian doctrines, including the Trinity. In his autobiography and letters, he expressed doubts about core Christian tenets, favoring a rational, moral approach to religion over metaphysical claims like the Trinity.
• Thomas Paine: Though not a political founder in the same sense, Paine, the author of Common Sense, was a vocal critic of traditional Christianity. In The Age of Reason, he explicitly rejected the Trinity, arguing against the divinity of Jesus and advocating for a Deist view of a singular God, dismissing Trinitarianism as irrational.
• George Washington: Washington’s religious beliefs are less clear, as he was private about his faith. He attended Anglican (Episcopal) services but avoided explicit references to Christian doctrines like the Trinity in his writings. Some historians suggest he may have held Deist or non-Trinitarian views, but evidence is not definitive.
• James Madison: Madison, the "Father of the Constitution," was also reserved about his beliefs. While raised in an Anglican household, his writings suggest a rationalist, possibly Deist, perspective, and he avoided endorsing Trinitarian theology, though he did not explicitly reject it in surviving records.

Note: The term "Founding Fathers" typically includes figures like those above, but beliefs varied widely. Others, like Alexander Hamilton and John Jay, were more orthodox in their Christianity and likely accepted the Trinity, though Hamilton’s views fluctuated over time. Evidence for non-Trinitarian beliefs often comes from personal letters, writings, or affiliations with Unitarian or Deist thought, which were common among Enlightenment-era intellectuals.

If you want a deeper dive into any specific figure’s beliefs or primary source quotes, let me know!