The Board of Trustees records, bulk 1857-1989, provide a comprehensive view of the decision-making process at the Peabody Institute. The trustees communicated with scholars and artists here and abroad seeking their advice on the formation of the institute. Their replies, many of them minutely detailed, can be found in the correspondence files of the trustee committees. Also included are letters from George Peabody to the trustees.

The collection is arranged in six series. Series A contains minutes of board meetings and committee meetings, as well as reports by officers and committees to the full board. Series B contains general records of the board. Series C contains files of officers, most notably the president and treasurer. Series D contains the records of 16 standing or ad hoc committees established by the board. Series E contains legal documents, including deeds and building records. Series F contains documents related to the Peabody Institute's decision to affiliate with the Johns Hopkins University in 1977, and subsequent legal and operational concerns in the 1980s.