Inchcailleach is an island in Loch Lomond. The church of St Kentigerna survives as excavated footings only. It was a rectangle measuring 21.65 metres by 7.85 metres over walls 1 metre in thickness, and there was a wall separating chancel from nave located 7.16 metres west of the internal face of the east wall. Evidence was found of two doors in the south wall, one in the chancel and one in the nave. The south nave door had two orders supported by en delit shafts on water-holding bases, and two simple waterleaf capitals were found with incised lines running parallel to the outer edges of the leaves. One order of the door had a triplet of keeled rolls to the arch. Four voussoirs of a larger arch order, which was thought to have been from the chancel arch, had three rolls separated by spurs.

The island is particularly associated with St Kentigerna, who is said to have been a hermit here, and whose date of death is traditionally given as 733. According to the Aberdeen Breviary (printed in 1510) she was of Irish origin, and was the sister of St Comgan of Lochalsh and the mother of St Fillan of Strathfillan. The name Inchailleach, which can be translated as the isle of the old women, has often been taken to mean that it was the location of a nunnery, though there is no evidence to support this, and it is significant that the Scotichronicon, written in the 1440s, refers to it as no more than the location of a parish church.

The parish was relocated to Buchanan on the mainland in 1621 and the church abandoned, though the churchyard continued in use for burials into the nineteenth century. The church was excavated in, or shortly before, 1899.