On December 21, 1864, seven months after the creation of the Montana Territory, Council Bill 15 was introduced into the Territorial legislature by Francis M. Thompson, a representative from Beaverhead County who would only live in Montana two and a half years, to create the Historical Society of Montana. The bill, "An Act to Incorporate the Historical Society of Montana", was signed into law February 2, 1865 "in order to collect and arrange facts in regard to the early history of this Territory, the discovery of its mines, incidents of the fur trade, etc." and was incorporated by Hezekiah L. Hosmer, Christopher P. Higgins, John Owens, James Stuart, Wilbur F. Sanders, Malcolm Clark, Francis M. Thompson, William Graham, Granville Stuart, Walter W. deLacy, C.E. Irvine, and Charles S. Bagg. The society is the second oldest state historical society west of the Mississippi River. On March 25, 1865, members of the society elected Wilbur Sanders President, Granville Stuart Secretary-Treasurer, and the Honorable Hezekiah L. Hosmer Historian. At the time of its founding, Granville Stuart was a merchant, Walter deLacy was the Territorial Surveyor, Hezekiah Hosmer was the Chief Justice of the Territorial Court and Wilbur Sanders was prominent in the Virginia City vigilante movement.
