Hammonasset's facilities consisted of 3 buildings, plus a maintenance garage on 56 wooded acres, bordering the Hammonasset River in Madison, CT. Although the school closed many years ago, the buildings still stand and live on to this day as the Madison Town Campus. If not for the town's purchase of the property, it would likely have been sold to a residential developer and destroyed.

The main academic building housed all of the administrative and classroom space, as well as a large open area called "the commons", which featured large soft chairs and a working fireplace. When not in class, this was where many students spent their time. It was the social nerve center of the campus. Also included in the commons was a conversation "pit" (a large, sunken, section of open floor space) where the whole school meetings were held. The main classroom space was referred to as "The Learning Center". It was a large open area consisting of the school library, surrounded by classroom "bays". The science lab, on the opposite end of the building was the only traditional classroom on the campus. Today, the main building serves as the Madison Town Hall, and has been extensively renovated. The fireplace is the only recognizable feature remaining in the building.

The Arts Barn consisted of a large open area for performing arts and included lighting and sound systems. Surrounding this area were various spaces for fine arts and music. The Arts Barn has undergone only minor renovations over the years and looks much as it did while the school was in operation. The building now houses a youth center and Madison's community access TV facilities.

Although seldom used, the main building and Arts Barn were equipped with air conditioning - a feature not seen in many schools in that era.

The gymnasium building included locker rooms, a dance studio, first aid room, and fitness equipment. The building is largely unaltered from it's original state but has been very well maintained by the Town of Madison. It is currently available to residents of Madison for recreational programs and includes a larger, modern fitness center.

Outdoor facilities included 2 large athletic fields, tennis courts, and hiking trails, which all still exist today. The hiking trails are open to the general public, even those not residing in Madison.