This collection consists of three volumes of original letters relating principally to the Louisbourg Expedition of 1745-1746. Representative of the contents are letters to or from Robert Auchmuty, Charles Chancy, Thomas Cushing, Samuel Waldo, and other important figures of the day.

Scholars should also refer to the Louisbourg Papers, which is included in this series of Massachusetts Historical Society collections, for more material relating to Pepperrell.