Located beside the road from Corofin to Kilfenora, with the stump of a round tower to the N of the church. Only the W wall and parts of adjacent side walls are medieval. The W wall has antae which terminate four or five courses below the top of the side walls. There is a round-headed S doorway with a chamfered soffit roll, over which is a Sheela-na-gig. Nave dimensions c. 21 m x 6.9 m approx. (Westropp 1900).

Early history obscure, but the presence of a round tower close by the church indicates that there was a monastic church preceding the parish church. The church is first mentioned in the ecclesiastical taxation of 1302-6. It was in ruins in 1615, and repaired in 1715 (Mac Mahon, 15; Harbison, 1970/92, 65). A Tau Cross originally located by the road (serving as a boundary marker) at Roughan, to the N of Killinaboy (NGR R.25.92), was removed in 1866, replaced in 1894, and removed again in 1967 to the Clare Heritage Centre, Corofin.

The Tau cross (see Corofin, Co. Clare) was identified as a Romanesque boundary marker by Rynne (1962). Harbison (1992, 128-9) suggests that the cross may have served as a guide to pilgrims to the church at Killinaboy. An incised slab in Killinaboy churchyard, probably of the 13th or 14thc., depicts a tau crozier and a bell (Rynne, 162). Harbison (2000) suggests that Killinaboy may have formed part of an ancient pilgrimage route in N Clare, linked with Rathblathmaic, Dysert O'Dea and Kilfenora.

The original construction of the church and double-armed cross appears to date from the early 13thc. (Harbison, 1976, 3-12). The W wall of the church appears earlier than the side walls, and to have been raised to their height at a later date. The NW anta is probably in situ, while the SW anta and most of the gable were reconstructed in the 15th or 16thc, incorporating the earlier double-armed cross. Harbison suggests that the cross was originally placed centrally over a lintelled W doorway, possibly reflecting the presence of a double-armed cross (a reliquary of the True Cross?) in the church (as at Caravaca, Spain). The double-armed cross, of Byzantine origin, was introduced in Europe in the 11th or 12thc and became particularly popular from the 13thc on.

The two other re-used fragments also appear to date from the early 13thc. Their original function or setting is uncertain, but both appear to have been designed to be set vertically, in a doorway, chancel arch, interior niche or tomb recess in the church (Fisher, 1990, 34). The lion head is reminiscent of door handles in the form of bronze lion heads. The rounded modelling of the lion head, the style of the palmette-leaves and the inclusion of dogtooth relate to 'Transitional' sculpture at sites such as Cong and Boyle. Other examples of dogtooth are found in Ireland at Grey Abbey, Gowran, Graiguenamanagh, Kilkenny, Athassel, Kilmallock, and Abbeyknockmoy.