Two years after the foundation of the first Girls' Public Day School Trust in 1873, Laura Lady Buchan, gave ￡1,000 to promote a 'higher class female education' in the Isle of Man. Her plan was vigorously promoted by Sir James and Lady Gell, supported by the trustees of King William's College and on 14 October 1878 Miss Louisa Moss, the first headmistress, welcomed 17 girls to Castletown High School for Girls in Stanley House, Castle Street.
When Miss Dawson arrived 30 years later in 1908 there were just nine pupils. Frequent changes of staff and premises and lack of endowment had brought the School to the brink of closure, but Miss Dawson's 11 years as headmistress turned around its fortunes. She took the School into new premises on the Green, developed a modern, liberal curriculum and saw day and boarding numbers rise ten-fold. Her achievements were matched by Miss Matthew; during her f15years of service the School became a direct grant foundation, supported by the Isle of Man Council of Education, and became known as The Buchan School.
In 1935 Miss Matthew's successor, Miss Tregear, found the school once again facing gloomy prospects, but with energy and ingenuity she guided it safely through the turbulent war years. Although Tynwald rejected proposals for a new building to replace the increasingly inadequate premises at Bowling Green Road, timely help came in 1940 when Sir Mark Collett gave ￡4,000 from the Ballamanagh Trust for the purchase of Westhill as a home for the growing number of boarders.
A period of remarkable and imaginative development began in 1960 with the appointment of Mrs Jessica Watkin to lead the school. During seventeen years of distinguished service she rebuilt the curriculum, raised the roll to 355, of whom 92 were boarders, and facilitated the consolidation of the whole School in modern premises at Westhill.
From 1977 the future was overshadowed by the Isle of Man Board of Education's decision to offer only 15 more years of direct grant funding. The School had no endowment to draw on, and consequently in 1991 The Buchan School and King William's College amalgamated to form one independent foundation.
Today The Buchan School at Westhill is the King William's College junior school for boys and girls aged 4-11.