The parish of Rathclaren has existed from at least 1291, the present church being either the third or fourth to have existed within the parish.  Church of Ireland archives state that the present building was erected in 1650 as it is today without the tower.  The belfry tower was added to the west porch somewhere between 1860 and 1875.

Surviving records for the church go back as far as 1780.  Church services occurred every Sunday, on major festivals like Christmas and Ascension and others saints' and holy days.

The parish appears to have organised an orphanage.  The orphanage and a self run parish primary school were sited on a plot of land currently occupied by the Kilbrittain Creamery at the top of the hill.

The parish of Rathclaren has had link ups with Timoleague, Templetrine and Kilbrittain in relation to parish oversight and staffing by clergy.  Kilbrittain appears to have had no active church building from about 1834 and services were held in Riversdale School House.  That seems to have continued until 1930s when the school was changed to a parish hall and the Church of Ireland parishioners joined the Rathclaren congregation in Rathclaren Church.

The clock in the tower was added in 1876 after the tower itself had been built and was a gift from Ludlow Sealy of Burren House. In 1896 a peal of ten tubular bells (very rare in Ireland) was given and installed in the tower in memory of three Sealy brothers, all of whom had for many years played a major part in managing the affairs of the parish, by name James, William and Ludlow.  The chimes can be rung by a single person pulling on a row of hand ropes either in rounds or reproducing hymn tunes.  The clock chimes the hour and has a special bell of traditional shape for telling the time.  A bell expert visiting the church many years ago records noting a bullet hole in the copper face.  This ties in with the reported ambush in 1921 by the IRA, hiding in the church grounds, of a consignment of timber, escorted by British soldiers, being taken to Burren pier for shipment to England.

These notes about the Parish of Rathclaren have been taken from the booklet entitled 'A History of Holy Trinity Church and Parish of Rathclaren' which was written by Revd Brian Harvey and was presented to the Bandon Local History Society on 18th July, 2001.