Page "Religious affiliations of Presidents of the United States" Paragraph 35

#* The Adamses were originally members of Congregational churches in New England.

By 1800, most Congregationalist churches in Boston had Unitarian preachers teaching the strict unity of God, the subordinate nature of Christ, and salvation by character.

Adams himself preferred Unitarian preachers, but he was opposed to Joseph Priestley's sympathies with the French Revolution, and would attend other churches if the only nearby Congregational / Unitarian one was composed of followers of Priestley.