The First Unitarian Church of Salt Lake City records (1891-2010) is a rich collection of source materials, containing primarily original documents tracing the history and activities of the Unitarian Church in Salt Lake City. It is organized into 221 boxes of records dating from its founding in l89l up to 2010. The Unitarian Church has been an advocate of many causes and has played a vital cultural role in the Salt Lake City area.

The Lorille Horne Miller papers (1938-1991) contain correspondence, newsletters, meeting agendas, maps, and pamphlets related to the 1977 National Women's Conference in Houston, Texas. In addition, there are news clippings related to the activities and membership of the First Unitarian Church from 1938-1946.

The Philip S. Thacher papers (1971-1989) contain biographical materials, photocopy of a scrapbook detailing his activities and a photocopy of a letter to the First Parish Church of Needham, Massachusetts "on its Bicentennial Anniversary." Thacher was a pastor of the First Unitarian Church of Salt Lake City, Utah.