Ontario Secondary School Teachers' FederationDistrict 16110 Pony Dr., Unit 6Newmarket, ON L3Y 7B6HomeWelcome to District 16 York RegionFounded in 1919, OSSTF/FEESO represents almost 60,000 educational workers throughout Ontario. The union works to protect its diverse membership which is represented in 140 bargaining units across the province.Locally, OSSTF District 16 was created in 1998 as a result of the amalgamation of the Ontario School Boards. more... See more text