Inchmarnock is a small island off the west coast of Bute in the Firth of Clyde.
Between 2000 and 2004 a wide-ranging programme of survey and excavation of multiple sites throughout the island was undertaken by a team from Headland Archaeology as part of a wider environmental audit on behalf of its new owner.
Among the sites investigated was a rock shelter with Late Iron Age and early medieval occupation deposits, medieval corn-drying kilns, and a building platform on which a 17th-century turf-built longhouse was erected, masking medieval and early medieval activity. But the key site to understanding the island’s history is the 12th-century church whose robbed-out foundations were left partially exposed after local excavations in the 1970s. The Early Christian origins of the site have long been recognised through discoveries of early cross slabs; now radiocarbon dates clearly indicate activity from at least the third quarter of the 1st millennium AD. A late medieval literate presence, possibly associated with regulation of pilgrimage activity on the island, is also clearly evidenced.