Ratheniska N.S. is a four-teacher school located on the outskirts of the fast-developing midland town of Portlaoise.  Idyllically situated under the watchful eye of the ancient fort of Dunamaise in lush, rolling Laois farmland, the school looks out on a vista of peace and tranquillity. Centred in one of the earliest areas of civilisation in Ireland, uniquely mentioned by the cartographer Ptolemy in the first century AD, the school and its community are aware of their heritage, while at the same time recognising the needs of a modern, vibrant Irish society.  

Records for the diocese of Kildare and Leighlin document two schools in the area which predate Catholic Emancipation and the National School System.  One of these schools was located in the chapel and the other in a small nearby cabin.

The present school was officially blessed and opened on Sunday 10th of January 1954.  An extension was added and extensive renovation took place in 1986.

There is a current enrolment of 111 pupils.