Half-Shire was founded on November 15, 1972, by six residents of northern Oswego County. They sought to form an organization that better represented the unique history of the northern section of the region. (The name Half-Shire refers to the founding of the country in 1816, settling a regional/political split by which the duel county seats were created: one at Oswego and the other at Pulaski.) In 1975, the Half-Shire Historical Society received its provisional charter. In 1978, the Society was permanently chartered by the New York State Education Department.