Situated on the former site of Fort Shirley, this three-story Colonial-style structure, circa 1761, is the only pre-Revolutionary courthouse that remains standing in the state. At the time of its construction, the 45-ft by 44-ft courthouse was the tallest building north of Boston. Both main doors open into a wide central hallway, each facing one of the main transportation routes of the day,- the Kennebec River and the King's Highway. Other unique architectural features include third-story musket ports, shiplap walls with no interior studding, a secret panel for hiding valuables, and a skylight for ventilation or watching river activity.
Listed on the National Register of Historic Places, former Presdident John Adams once tried a case in this building. Today, furnished courtrooms, living quarters, and judges' chambers display period items July-August. Special programs and activities are sponsored seasonally, and group tours are available.