The Thetford Historical Society was founded in 1943 by a group of local people interested in local history. Among these were Rev. William and Mary B. Slade, who spent many years delving into family and institutional records of the area; Charles and Fannie Hughes, who were fascinated by local artifacts and crafts and processes; Richard J. Fowle, a zealous guardian of local institutions, and Emma Coombs, teacher, librarian, moving spirit of the local Grange.

At first, the Society simply had summer meetings. In the late 1940's, the Hugheses had collected at auction enough tools and artifacts to have an exhibition in a borrowed barn. In 1950, the collection was formally called a museum, and exhibits became yearly. In 1960, the Society took a large part in celebrating the bicentennial of the Town’s charter. One offering was an historical map by Charles Latham with the help of Kenneth Cook. Two years later, a bequest from Emma Coombs of her barn gave the Society a permanent home.

In the late 1960's, the Society’s board began working toward a library building to hold records and books collected by several members. Latham Memorial Library, whose original building had burned in 1942, made this a joint project. A library federation was formed; building plans were made and improved; and a new building, financed by federal funds and private donations, became the Town’s project for the national bicentennial. The building opened in 1975, giving the Society’s library a free home.

In the past 30 years, the Society has published several books on local history, and in the past two decades additions have been made to the Barn Museum: three stalls from the Thetford Center Horsesheds, and two other buildings, one for exhibits and one for storage.