King William's College (Colleish Ree Illiam in Manx) is a leading world International Baccalaureate HMC independent school for ages 3 to 18, situated near Castletown on the Isle of Man. The College is located on two sites in Castletown; the main estate which takes pride of place on the shore of Castletown Bay, and The Buchan School which is the College's preparatory school, located in the Westhill part of Castletown, some two miles from the main campus. The College, known as KWC or to the local people as King Bill's, widened entry from boys-only to co-educational in the 1980s. Today there are roughly 500 pupils, many of whom are international.