In 1975 the Braintree Historical Society (BHS) erected a colonial style barn as a complimentary addition to the General Sylvanus Thayer Birthplace. The post and beam construction of the barn is consistent with that of early American structures of its style. Although it is commonly referred to as simply “the Barn,” the structure’s official name is the Gilbert L. Bean Barn Museum. The Barn houses artifacts that would typically appear in colonial America.
In 1995, the BHS completed an addition to the Barn, the Mary Bean Cunningham Historical Resource Center. The main level of this building houses the Society's library and resource center, and contains genealogical information on many prominent Braintree families. The lower level houses several thousand of the Society's collection items stored in a climate-controlled environment, where they are accessed periodically for rotating exhibits.
Currently, the facility is being remodeled and is only open periodically upon request and during Society sponsored events. The Society will host a Grand Re-Opening of the Library and Resource and Barn in the Fall of 2018.