First published in 1788 and later adopted in 1791, the rules, bylaws, and act of incorporation of the Massachusetts Humane Society are located in three folders. The rules, bylaws, and act of incorporation of the Humane Society establish the number of trustees and officers that are allowed to serve, responsibilities of the trustees and officers, frequency of Society meetings, monetary awards and medals given to rescuers, and other important aspects of the Society. The rules and bylaws have been amended over the course of the Society's existence.

Eleven volumes of minutes contain records for monthly and annual meetings of the Humane Society of Massachusetts held in Boston, Mass., usually at a board member's house. Monthly meetings recorded attendance, presentations of rescue cases, and votes on awarding medals or money. Annual meeting minutes recorded the election of officers and trustees and discussions about the budget.

Membership-related records include a list of member names, some noting their place of residence, from 1786 to 1838, and a list of men who delivered the annual discourse to the Society from 1787 to 1817.

This folder contains the history of the establishment of the Asylum for the Insane, an agreement made between the Humane Society of Massachusetts and Massachusetts General Hospital.

Seven volumes of treasurer reports record payments for materials and supplies, employee salaries, upkeep of lifesaving stations, lists of property including real estate, stocks, bonds, investments, and names of subscribers and annual subscriptions paid to the Society. Also included is an account book kept by Charles Amory, the Society's treasurer, from 1849 to 1864. Amory's entries include travel reimbursements for members, payments for silver and gold medals, rewards for lifesaving heroics, materials and supplies, and returns on investments and stocks.

Three account books of the Humane Society record payments to companies for work performed at lifesaving stations, materials, supplies, outstanding bills, and employee salaries.

One volume of bills and vouchers of the Humane Society kept from 1848 to 1849 records supplies such as lumber for building boats and lifesaving stations, cordage for ropes, and copper for boat hulls. Entries were made at various locations in Massachusetts. including Boston, New Bedford, Chatham, Hull, Edgartown, and Kingston.

In one folder containing valuation lists of property owned by the Humane Society of Massachusetts from 1786 to 1916, one list records the total value each year, and the other records property values in ten-year intervals. Also included is the name of the Humane Society treasurer and the years served.

Estate inventories, wills, and probate records consist of monetary gifts given to the Humane Society upon the death of the donor. Many of these donations became the backbone of the Society's endowment. See treasurer reports for the performance of the gifts.

Audited financial reports of the Humane Society from 1969 to 2004 record income gained from investments in stocks, bonds, and securities.

A 1939 report on restricted funds belonging to the Humane Society sought to document whether or not the restricted funds were being used in accordance with the original wishes of the donor. These funds include legacies, wills, and donations.

Lifesaving rescue and case reports record the location of an accident, names and addresses of person or people who made the rescue, names of people saved or lost, witness names and addresses, cause of the accident, correspondence related to the case, and any newspaper clippings regarding the case.

Three volumes recording the location of sixty-eight lifesaving stations and lighthouses located on the Massachusetts shore consist of detailed lists of the amount of equipment kept at each station, including oars, sails, life-belts, buckets, blankets, etc.; the condition of the equipment; the name of the keeper and active captain of each station; structures located on the property of the lifesaving station, including boathouses and houses, what condition the structure was in, and the year it was built and painted. Also included are the dimensions of the lifesaving stations, boathouses, and boats located at each station.

One logbook kept by the recording secretary includes daily entries listing medals awarded, improvements needed at stations, supplies ordered and received, sale of stations, and transfers of supplies and materials between stations.

One folder containing reports of the lifebuoy service provided by the Humane Society from 1950 to 1961 record the location of the buoys, number present, condition, date last replaced, number of buoys sent, and the person responsible for the buoys.

Nineteen letterbooks of retained copies of outgoing correspondence include letters written by Robert Bennet Forbes, Benjamin W. Crowninshield, and Sidney W. Burgess regarding all aspects of the Humane Society, including outfitting lifesaving stations with new equipment and supplies, sale of old boats, lifesaving boat construction and design, condolence letters to families of accident victims, payroll numbers, and money and medals awarded.

Papers relating to the affairs of the Humane Society of Massachusetts include correspondence written by Thomas Motley, Jr., James F. Alcorn, and Benjamin W. Crowninshield. Also included is a folder of letters and the deposition of James F. Alcorn concerning the wreck of the brig Metropolis and subsequent rescue efforts of the Humane Society. Other loose correspondence from 1950 to 1961 includes letters written to and from Alexander Houston, secretary of the standing committee, regarding the lifebuoy program initiated by the Humane Society, and correspondence from 1950 to 1969 between the Humane Society and the United Fund of Massachusetts regarding donations and contributions made by the Humane Society.