Washington and the family he was raised in were originally Anglicans. The Episcopal Church was not officially founded as a separate province within Anglicanism until 1789, after the American colonies proclaimed independence from Great Britain. Prior to the American Revolutionary War, the Episcopal Church was part of the Church of England, so Washington was originally a member of the Church of England.
While he was President, Washington attended Christ Church (an Anglican/Episcopalian congregation) in Philadelphia.
George Washington has frequently been described as a "Deist." Washington is not known to have described himself using this word, nor is he known to have been been a member of any Deist organizations. Some writings by George Washington indicate Deist beliefs; other writings indicate non-Deist beliefs.
Although he was an Anglican and an Episcopalian, Washington reportedly did not take communion and was not considered an official "communicant" (full-fledged adult church member).
It is generally agreed upon that Washington's beliefs could be described as "deist" during at least part of his life. Deism for Washington, as with most historical figueres classifed as deists, was never an actual religious affiliation, but was a classification of theological belief. As nearly all major political figures from Washington's era can be described as "deists" if a sufficiently broad definition is used an if the correct quotations are selected, classifying Washington as a Deist may not by particularly useful or distinctive.
Although the Episcopal Church is the only denomination Washington ever attended with any regularlity, he was not particularly dedicated to the denomination nor did he have a strong Anglican or Episcopalian self-identity. During Washington's era there was no real notion that he was a "non-Christian," and his denominational affiliation certainly placed him well within "mainstream" Christianity at the time. But Washington's religious beliefs could be classified as relatively broad and non-specific. His disinterest or disbelief in some mainstream Protestant Christian beliefs have led later (usually partisan) commentators to label Washington as "non-Christian."
George Washington was identified as an Episcopalian by the 1995 Information Please Almanac; the Library of Congress; and A Worthy Company: Brief Lives of the Framers of the United States Constitution by M. E. Bradford. Memoirs & Correspondence of Thomas Jefferson, IV, page 512 was cited as the source stating that Washington was a "theist." (Source: Ian Dorion, "Table of the Religious Affiliations of American Founders", 1997).
From: Robert G. Ferris (editor), Signers of the Constitution: Historic Places Commemorating the Signing of the Constitution, published by the United States Department of the Interior, National Park Service: Washington, D.C. (revised edition 1976), pages 214-218:
Peerless military leader of the War for Independence, able chairman of the Constitutional Convention, brilliant first President, and wise statesman, Washington more than any other man launched our Republic on its course to greatness. For these reasons, he clearly deserves the epithet "Father of His Country."From: Rick Shenkman, "An Interview with Jon Butler ... Was America Founded as a Christian Nation?", posted 20 December 2004 on History News Network website (http://hnn.us/articles/9144.html; viewed 30 November 2005):
Washington enjoyed only a few years of retirement at Mount Vernon... He died at the age of 67 in 1799. In his will, he emancipatd his slaves.
Mr. Butler, Dean of the Graduate School of Arts & Sciences at Yale University, is the author of Awash in a Sea of Faith: Christianizing the American People (Harvard University Press, 1990). This interview was conducted by HNN editor Rick Shenkman for The Learning Channel series, "Myth America," which aired several years ago...
[Interviewer:] Let's go through some of [the Founding Fathers]. George Washington?
[Jon Butler:] George Washington was a man for whom if you were to look at his writings, you would be very hard pressed to find any deep, personal involvement with religion. Washington thought religion was important for the culture and he thought religion was important for soldiers largely because he hoped it would instill good discipline, though he was often bitterly disappointed by the discipline that it did or didn't instill.
And he thought that society needed religion. But he was not a pious man himself. That is, he wasn't someone who was given to daily Bible reading. He wasn't someone who was evangelical. He simply was a believer. It's fair, perfectly fair, to describe Washington as a believer but not as someone whose daily behavior, whose political life, whose principals are so deeply infected by religion that you would have felt it if you were talking to him.
...The principal Founding Fathers--Washington, Jefferson, Adams, Franklin--were in fact deeply suspicious of a European pattern of governmental involvement in religion. They were deeply concerned about an involvement in religion because they saw government as corrupting religion. Ministers who were paid by the state and paid by the government didn't pay any attention to their parishes. They didn't care about their parishioners. They could have, they sold their parishes. They sold their jobs and brought in a hireling to do it and they wandered off to live somewhere else and they didn't need to pay attention to their parishioners because the parishioners weren't paying them. The state was paying them.