The Post Chaise Companion, published in 1805, states that:[citation needed] "Near Mountrath is an extensive bank containing, or rather, formed of excellent iron ore, within a few metres of the surface; here an iron and metal foundry has been established and wrought some years since with great success; but at present, from the scarcity of charcoal, on the destruction of the neighbouring woods, the furnaces are seldom employed; it is much to be regretted that such a valuable manufacture should be discontinued on the above account, as the country abounds with bogs, and charred turf might probably be substituted in the place of charcoal for most purposes.

Older leases granted on the Castlecoote estate, on which the town was built, were written in strict accordance with the Penal Laws, and contained a clause prohibiting the letting, selling, or bestowal of ground for the purpose of erecting a Roman Catholic Church.

In consequence of this prohibition, the place of worship used by local Catholics stood upon a sand-bank beside a tributary of the River Nore called 'The Brook".

Lord Castlecoote was publicly opposed to the proposal but the political climate of toleration that followed the Roman Catholic Relief Act 1793 encouraged the bishop.

This gentleman found Dr. Delany a suitable plot from his own landholdings and shortly after, through his influence with the proprietor, procured a perpetual peppercorn lease as a site for a parish church.

[citation needed] In October 2017 the Brigidine Sisters gifted the convent to the community of Mountrath for the long-term benefit and development of the town and surrounding areas.

Hundreds of pennies have been beaten into the bark as good luck offerings, until they eventually killed the tree but it began to sprout new shoots from its trunk and is growing again.