The Belchertown State School Administration Building was constructed between 1926-1927 and designed in the Colonial Revival style by the prominent Boston architectural firm of Kendall, Taylor & Co. The modest building is closely modeled on its 1915 predecessor at the Wrentham State School.
As originally constructed, the Administration Building consisted of eight rooms on the first floor, including the superintendent’s office, assistant superintendent office, medical office, stewards office, steward’s clerk, bookkeeper, reception and secretary.
The ground floor featured a medical library, stenographer’s office, social worker's office, and examination rooms. The attic space above was unfinished.
In 1967, the similarly scaled and detailed rear ell was constructed to the west of the front block. The ell is connected to the front block by a brick connector block. Additional offices, examinations rooms and storage spaces were located on the three levels of the rear block.