On December 21, 1864 Francis M. Thompson introduced into the Territorial legislature, Council Bill 15 to incorporate the Historical Society of Montana, as a private organization. The purpose of the Society was “…to collect and arrange facts in regard to the early history of this Territory…." The bill was signed into law on February 2, 1865. The Society held its first organizational meeting later that month. Among the incorporators were Granville Stuart, H. L. Hosmer, C. P. Higgins, John Owens, and W. F. Sanders. The Society membership was limited to a few prominent Montana pioneers, who had to be elected by unanimous election by the members.

The Society began collecting reminiscences and other memorabilia of the early pioneers. Tragically, these collections burned in the disastrous 1874 fire in downtown Helena. Immediately after the fire, the Society contacted many of the original pioneers and obtained replacement reminiscences, diaries, and letters. They also began the intensive collection of the territory’s newspapers, publications of government expeditions, artifacts, and other items of interest. The collections were housed in the Lewis and Clark County Courthouse from 1886 until the completion of the new Capitol building in 1902.

The early history of the Society was one of a gradual increase in government involvement. In 1873 the legislature appropriated $150 to buy additional manuscripts and books. By 1887 the Territory was paying rent for housing the library and the salary of the librarian. In 1891 the collections were officially transferred to State control. And two years later the Governor was given the authority to appoint the Board of Trustees. In 1895 the legislature changed the name to “The Historical and Miscellaneous Library”. This name was retained until the 1923 legislature restored the original name. Finally in 1963 the name was changed to its present Montana Historical Society.

A separate building for the Society was planned as early as the mid 1920s, but the Depression, World War II, and other factors delayed the building until 1953 when the Veterans and Pioneers Building was completed. In 1951 K. Ross Toole was hired as the first professional director. His major task was to plan for the new building, and the varied programs which it would enable. Among these programs were a formal museum, art galleries, the library, and a magazine.

The original Historical Society of Montana was governed by a five member Board of Trustees consisting of the President, the Recording Secretary, the Corresponding Secretary, the Treasurer, and the Librarian. Beginning 1891, when the state legislature established the Historical Society of Montana as a state agency, the Board of Trustees was appointed by the Governor. In 1949 the Board was expanded to 15 members. From the Board of Trustees, an Executive Board is chosen consisting of the President, Vice President, and three additional Board members.

During most of its existence, the Board has played a secondary role, leaving the active management of the Society to the paid staff. The functions of the Board consist of overall policy decisions, approval of all deeds, leases, and other legal documents executed by the Society, and other duties as set forth in current legislation.