The DeWitt Historical Society was formed in 1935 as a revival of two earlier historical societies of 1863-64 and 1888-1905. The first, the Ithaca Historical & Scientific Society, was started by Ezra Cornell, and lasted for less than two years. DHS was first formed in 1899 to promote Tompkins County history, and was named in honor of Simeon DeWitt, a prominent early Ithacan.