In the early 1970s the Minister for Education, Michael O'Kennedy sanctioned the building of centrally located schools in parishes throughout Ireland. Up to this point most parishes had a number of small two or three teacher schools to serve the needs of the local community. Children in neighbouring townlands walked to school and their education was catered for in buildings that were built and designed during a period at the turn of the century. Multyfarnham was like most other parishes in Westmeath with three national schools dotted throughout the parish. Ballinafid NS, Leney NS and Multyfarnham NS catered for the needs of the children of the time. In 1971 it was decided that these three schools should be amalgamated and a new all purpose 5 classroom building should be built in or around the village of Multyfarnham. Logistically this was a major undertaking for the government of the time as it brought into being the school bus and no doubt change was approved cautiously. After much deliberation the site at Rathganny was chosen for the new school and in 1973 St. Cremin's N.S. opened its doors for the first time to the pupils of Multyfarnham parish.

Legend tells us that St. Cremin, our patron saint, was the nephew of St. Patrick, the patron saint of Ireland. St. Cremin established a church at Lacken, approximately 3 kilometers from the school. The ruins of the church together with a holy well dedicated to St. Cremin are to be found in the townsland of Lacken, not far from Leney Church. Again legend tells us that St. Cremin had a vision one night of the birth of St. Fechin, Abbot of the Abbey at Fore, approximately 7  miles from Lacken. It is said that St. Cremin built his church and monastic institute to replicate that of the settlement in Fore, Co. Westmeath.

St. Cremin's feast day is on the 28th June every year. 

During the 1990s the school saw the construction of its sixth classroom, together with a new staffroom. In 2019 a significant extension saw the construction of our seventh classroom, three Special Education rooms, a new secretary's office, a new library area and a link corridor. Due to increasing numbers another extension was constructed in February 2021 which included a link corridor and our eighth classroom.

Our school crest was designed by former principal Mr. John O'Reilly. Muilte Farannáin (Farran's Mill) the Irish for Multyfarnham is represented by the Old Mill wheel. The four swans on water represent Fionnuala, Aed and twins Fiachra and Conn, the four Children of Lir, who, legend tells us, spent 300 years on Lough Derravaragh in the parish of Multyfarnham after being magically changed into swans by their jealous stepmother, Aoife. The Church in the background represents the Franciscan Friary in Multyfarnham, a beautiful building originally founded by the Franciscan order in 1268. The Friary is a significant part of our parish history.

Mr. Donal Byrne (RIP) was the first principal of St. Cremin's NS in September 1973. After a brief period he was replaced by Mr. John O'Reilly in 1974. Mr. O'Reilly remained as Principal of the school until his retirement in 2006 when he was replaced as principal by Mr. Niall Brennan. Mr. Brennan remained as principal in the school until November 2015. Following his appointment as principal in Loughegar NS, Mr. Karl Dermody, the current principal in the school, was appointed to position.