In 1648 the increase in population in this area necessitated the break up of the large parishes of Rosneath and Cardross and the creation of a new parish of Rhu.
The first small Rhu Parish Church was built on the very site where we worship today. As time went by, the population of the parish increased and the church became too small. A second church was built on this site. In those days the Kirk Session had considerable powers over the lives of parishioners. Wrongdoers could be fined or worse be summoned to the Repentance Stool (known as the Jaggs) in church there to receive a public rebuke from the minister in front of the whole disapproving congregation.
Then in 1851 a third church was built – the very church we now sit in. But before this, Rhu like so many of the other parishes in Scotland suffered a crisis of conscience leading to the disruption of the established church and the creation of the free movement. Those members of the parish who joined the free movement at first met to worship in a granary on the site where the house, Aldonaig, now stands. Then in 1844 they opened their own free church in Shandon at the foot of Kirk Brae.
1929 saw another change, with the union of the free church with the established church. Once more there was spiritual unity within the parish. In due course logic and economics led to the closure of Shandon Church. Once again Rhu Church was the spiritual centre of the Rhu & Shandon Parish.