The Unitarian denomination has venerable European and British Island roots commencing at the time of the Protestant Reformation. Its development in the United States preceded the American Revolution in a number of the old congregational churches of New England.

Unitarians are opposed to a central authority and devoted to three leading principles: complete free religious thought rather than bondage to creed or dogma; unrestricted use of reason in religion, rather than reliance upon external authority or past tradition; and generous tolerance of differing religious opinions and usages, rather than insistence upon uniformity in doctrine, worship, or polity.