Built from 1798 to 1800, the Octagon House is a three-story house made of bricks that is patterned to its irregularly shaped lot. This architectural landmark is famous because of its contemporary structure, breaking from the traditional Federal and late Georgian house construction that followed it. The Octagon House epitomizes the American Federal architecture with its various structure combinations such as two rectangles, a circle and triangle. The exterior and interior decoration exudes the art of elegance and restraint.

In 1899, the Octagon House became the home for the American Institute of Architects. Inside the mansion, it houses vast collection of imported furniture and home d?cor from England. In 1996, the Octagon underwent extensive renovation to restore its unique architectural appearance.

The mansion is available for tours by appointment.