King William's College (Manx: Colleish Ree Illiam) is a co-educational private school for pupils aged 3 to 18 near Castletown on the Isle of Man. It is a member of the International Baccalaureate and Headmasters' and Headmistresses' Conference organisations. The College operates at two sites: a main senior school campus on the shore of Castletown Bay, and a prep school (The Buchan School) in the Westhill part of Castletown. The College was originally for boys only, but became co-educational in the 1980s. It has roughly five hundred pupils. The UK Department for Education categorises it as an Overseas British school. Source: Wikipedia (en)