The frigate Essex papers consist of ships' papers, correspondence, account books, bills, and receipts. Although the papers run from 1798 to 1974, the bulk of the material is related to the construction of the frigate in 1799. The collection has been divided into two series.

Series I. Frigate Essex Papers includes correspondence, contracts, memoranda, accounts, account books, bills, and receipts that document the construction of the vessel, and has been divided into four subseries.

Subseries A. Correspondence provides a detailed look at the process of construction and naval administration in the early years of the American Navy. Other than the letters of nationally prominent individuals listed in Appendix I, the correspondence includes items from Jacob Sheaf (the Navy Agent at Portsmouth, New Hampshire), William Winder and Thomas Turner (both Accountants of the Navy), and Robert Gill (naval storekeeper, Philadelphia). Joseph Waters' letter book contains his outgoing correspondence concerning the Essex and his duties as Naval Agent. There are photocopies of letters in this subseries; it is unclear where the originals are, or when the photocopies were made.

Subseries B. Contracts, Specifications, and Supplies contains contracts and agreements that relate to various phases of the ship's construction, procurement of various ships' stores, and appointments of attorneys to receive the back wages of some individual crew members. They do not include the contracts made with Enos Briggs or William Hackett. The dimensions and specifications are mostly concerned with rigging, but a comprehensive memorandum of hull specifications signed by Hackett and Briggs is included. The folder "Indents for Supplies" consists of orders for items needed by the ship's purser, sailing master, cooper, surgeon, carpenter, boatswain, gunner, and armorer. The ship's stores memoranda were probably used in the production of the indents mentioned above. This subseries also includes a manuscript "Table of the Component Parts of Rations for the Navy of the United States" published in 1799. Included in this series are some photocopies of materials, the originals of which are not in the collection. Some of the photocopies have a note that the original copy is owned by "L. W. G."

Subseries C. Financial Papers contains financial and account information related to the ship, including bills and receipts. Included in this subseries are abstracts of allotments, which are lists of crew members and their wages along with the names of individuals, designated to receive portions of each crew members' salary. Miscellaneous accounts are comprised of statements of items shipped from other naval agents in New York, Boston, Philadelphia, and Portsmouth, New Hampshire. These miscellaneous accounts include a list of expenditures related to the launching of the Essex.

Subseries D. Other Papers includes an undated list of cabin furnishings and transcripts. The transcripts were produced by Philip Chadwick Foster Smith in preparation for the publication of these papers by the Peabody Museum. The introduction to the transcripts describes the categories in which Smith originally arranged the collection and provides a detailed subject index that refers to pages in the transcripts. Although there are transcripts for the vast majority of the items in the collection, this compilation is not complete.

Series II. Miscellaneous Ships' Papers is comprised of materials relating to the Essex while in the service of the British government and papers concerning other vessels which may relate to the design or construction of the Essex. All of the materials relating to the Essex while it was in the service of the British government are photocopies. The photocopies are from the National Archives of Ireland (formerly the State Paper Office at Dublin Castle) and were made in 1973 at the request of the Curator of Maritime History of the Peabody Museum. The papers concerning unidentified British vessels consist of memoranda with dimensions of masts and spars for a thirty-two and a thirty-six gun frigate.