Dufferin County is a county and census division of the Canadian province of Ontario.The county seat is Orangeville, and the current Warden is Warren Maycock.The Current Chief Administrative Officer is Sonya Pritchard [1] . Dufferin covers an area of 1,486.31 square kilometres (573.87 sq mi), and its population is 56,881 (2011).our rivers — Saugeen, Grand, Credit and Nottawasaga — take their rise in Dufferin or in adjacent townships and drain through the county. The county is a lofty table-land that is about 1,700 feet (518 m) above sea-level and about 1,400 feet (427 m) above the level of downtown Toronto.