The parish of Dunleer, like many modern Irish parishes, is a patchwork of several smaller medieval parishes. These include Richardstown, Dromin, Cappogue, Philipstown and Dunleer itself. The present Church of Ireland building is thought to be the site of a monastic site. The monastery of Lann Léire is mentioned many times in the annals but it was finally destroyed in 1148, having been founded in the early eighth century. The founding saints were Saint Furadran and Saint Baothan.
Dromin was also a monastic site with a monastery founded by Saint Fintan. Opposite the old graveyard and medieval church ruins is the present Church, also dedicated to Saint Fintan. Philipstown Church is dedicated to Saint Kevin and the Parish Church in Dunleer is dedicated to Saint Brigid. A Holy Well dedicated to Saint Brigid was once a focus of devotion in the parish and there are stories relating to the restoration of eyesight that are associated with the well and the area. There are several other Holy Wells scattered around the parish.
The present churches were all built in the early nineteenth century. Dunleer church dates to about 1802, though there may have been a thatched structure on the site beforehand. Dromin was built in 1826 and Philipstown first appears in the records in 1836. All of these churches have been re-built or altered over the centuries, the latest being a complete re-ordering of the Parish Church in the early years of the present century.