The First Unitarian Church of Peabody Records consist of administrative records, financial records, records of pastoral activities such as marriages and baptisms, and records of church social activities. They are divided into four series.

Series I. Church Administration Records includes a volume with the original church covenant (1827) and members (1827-46); a record book that does not contains copies of church meetings but does contain copies of letters and church resolutions, the Rev. Edward I. Galvin's record of marriages, deaths, and church events (1868-71), the Rev. John W. Hudson's records of funerals and marriages (1873-1917), and a list of ministers (1898-1912) succeeding Hudson; and miscellaneous reports and correspondence, including a list of families in the Unitarian Society in 1889-90.

Series II. Financial Records includes a promissory note book (1826-29); pew assessments (1833, 1840-41, and undated); a treasurer's book (1890-98) that also includes bequests (1876-97) and insurance information (1894-1903); a treasurer's book (1909-18); bequests (1936-39); and miscellaneous papers removed from the treasurer's book (1937-46).

Series III. Pastoral Activities includes marriage, baptism, and funeral records. Notebooks kept by Rev. Charles C. Sewell list marriages (1827-42), baptisms and deaths (1827-32). A notebook compiled by Mrs. John W. Hudson (189?) includes copies of these same records: marriages (1827-41), baptisms (1827-32), and deaths (1827-32). The record book (B1 F2) includes information on funerals and marriages by the Rev. John Hudson (1873-1917). Programs for church services (1887-1938) and published copies of sermons by the Reverends Kippis, Lamson, and Hudson are also included here.

Series IV. Church Social Activities includes programs for minor dramas and plays, and club events. A handwritten account of the fiftieth anniversary celebration in 1876 supplies a detailed report on the history of the church and its several pastors and founders. Also in this series is an undated photograph of the church interior, and a newspaper article from 1873 on the history of the church.