The story of our school began on May 31st, 1853, on the feast of St. Angela. A group of Mercy Sisters left Galway and made their way to Castlebar. They saw the need for education of girls in the town and opened their first Primary School in 1854. It consisted of one large classroom.

In 1894 a large new school was built. The present school was built in 1963 with 10 classrooms, a remedial room, an assembly hall and a staff room. In 1972, 4 additional classrooms for the Infants were built. In 1989, another extension was added to accommodate the senior classes. The most recent extension, completed for September 2005, consists of 5 large classrooms and various renovations were also carried out to existing resource rooms and classrooms.

The school that was built in 1894 which still remains in the old convent grounds.