When Middlesex County was formed in 1785, the county seat was to be shared by Middletown and Haddam. As a “half-shire” town, Haddam was required to built a courthouse and jail. The first jail, constructed of wood, was built in 1786, followed by a brick structure in 1812. This was replaced by the gable-roofed section of the later Gaol (Jail) and County Workhouse, constructed in 1844-1845 with stone from the Arnold granite quarry in Shailerville. The workhouse and barn were added in 1855. The Mansard-roofed section, which more than doubled the size of the building, was added in 1874. The jail continued to hold prisoners until 1969 and the following year became the Correctional Academy for the state, since 1972 known as the Connecticut Justice Academy.