The church started life as one of Thomas Telford's Parliamentary Churches in 1829. Total cost of construction at the time was £1,473, which included building a manse and a byre. These churches tended to come to a standard design: "T" shaped preaching boxes, usually with galleries in each "wing" and everything focused on the pulpit.
The Old Church of Rannoch is differs significantly from the normal design, comprising a rectangular box with its focus at the east end under a high wood-clad ceiling. This is because what you see today actually owes rather less to its 1829 construction than to a major rebuild in 1893.
Signs of change remain evident to visitors today. Perhaps most strikingly, the west gable was once home to a rose window whose outline can still be seen in the stonework. Today this gable provides entrance to the church, via a wooden porch.
Internally there are other more subtle indications of change that moved the church away from its austere 1829 beginnings. Especially striking is a spectacular stained glass window in the south wall portraying the parable of the Good Samaritan and dedicated to the memory of "Charles Robertson late of Mulinvaddie and his wife Jessie MacGregor" and erected by their son Duncan.
Interestingly, although called the "Old Church" this is a very long way from being the oldest in the area. Christianity came early to Rannoch with the arrival of St Blane in the 500s. He established a chapel at Lassintullich, two miles to the east, which was said to have been consecrated with sacred sand from Iona. A stone ruin of indeterminate but probably rather later date stands on the spot today.