St. Mary's Church is named after the mediaeval Augustinian abbey which was located on the outskirts of the Parish called St.

[4] St. Mary's Abbey and its associated granges[5] were suppressed on the orders of King Henry VIII, the English monarch proclaimed King of Ireland, who suppressed religious orders throughout his English and Irish kingdoms, often forcibly, as part of his dispute with the Holy See over its refusal to grant an annulment of his marriage to his first wife, Catherine of Aragon.

The formal opening of St. Mary's took place on Sunday 20 October 1839 at High Mass offered by Bishop Cantwell.

[10] The church itself contains a monument commemorating the fact that it was built with the permission of the major landowner in the area at the time, the Duke of Bedford.

The Duke's family, the Russells, were also commemorated until recently in the name of a nearby hotel (since rebuilt and renamed).

The local Church of Ireland contains a balcony that was reserved for the duke and his family when they attended services there.

The current administrator is the Very Reverend Declan Hurley, Adm. St Mary's contains a famed wooden life-size sculpture of Christ on the Cross, hanging from the back wall behind the reredos.

The sculpture is by Edward Smyth, the 19th-century sculptor from County Meath famed for his riverine heads on the Custom House in Dublin[15] The Anglican church in Navan is also called St. Mary's Church and is a short distance away from the Catholic St. Mary's.

Among other religious groups that meet for services in Navan are the Elim Ministries[16] and the Calvary Community Church.