The location was the circa seventh century site of the cell of a St Fillan, probably a follower of Saint Columba, who was held in such reverence that his arm bone was one of the holy relics paraded in front of the Scots Army at Bannockburn.

The cult of St Fillan's was introduced by Irish immigrants and the church one of several that Walter fitz Alan, Steward of Scotland gifted to Paisley Abbey in 1169, a foundation that he himself established.

St Fillan is the patron saint of the mentally ill.[4] In 1781 it is recorded that the kirk was being used for services by the Cameronians, a radical faction of Scottish Covenanters from Sanquhar who followed the teachings of Richard Cameron.

The followers were also known also as "Society Men", "Sanquharians," and even "Hillmen" as they used remote sites to hold Conventicles, for example it is known that the isolated Kirkbride Kirk in Nithsdale was un-roofed in an attempt to deter its use by Covenanters.

[7] A square hole to the left of the door marks the site of the old parish jougs that were stolen, discovered by chance and donated to a local museum who have yet to locate them.

The church interior was used for burials in the 19th century with the addition of the Barochan Aisle, iron railings partitioning off the east end and plaques mounted on the walls in several places.

The church's manse, now Kilallan Farm or House, immediately adjacent to St Fillan's, is considered to be the oldest existing dwellinghouse in Renfrewshire.

[8] In 1950 a visitor recorded that the old glebe field was exceptionally fertile in comparison with other parcels of land in the area and was traditionally regarded as being the old kitchen garden of the pre-Reformation priests.

It is reported that Shaw had been "betwitched" by the defendants and was exhibiting behaviours including flying, and was vomiting coal, hair, wool, bent pins, etc.

[10] The Rev Peter Dale was minister of the joint parishes of Houston and Kilallan from his induction on 5 September 1843 until his death on 11 December 1856 as recorded on a marble plaque on an interior wall.

Local tradition records that St Fillan sat in this chair, preached and baptised converts and babies with holy water from the cup that had been collected from the nearby well.

The holy water was thought to miraculously cure ailing children or those with rickets; pieces of cloth and rags being tied to overhanging branches at the well as votive offerings.

The radical Calvinist minister, James Hutcheson, had the well filled with stones in around 1690, however this was later cleared out as the water continued to flow and it was even piped to the old farm for domestic use that may explain the current presence of brickwork at the site.

[13][15] A drawing of 1923 shows the three courses of stone or brick as a 'U' shape pierced by an overflow pipe that passed the holy waters into an old rectangular porcelain sink set into the ground.