The research on the McCain 'clan' is still ongoing and new data is being discovered. At present, the research is concentrating on land records, charters, man-rents, etc., from the Caimbeul and Scrymgeour families in mid Argyll. The McCain family can be followed through these records from circa early anno domini 1400s into the late 1500s. The exact date groups of McCains left mid Argyll from Ireland is not known, but the records do suggest that this happened circa 1570.
Many of the mid Argyll families have very elaborate late medieval Gaelic pedigrees, however, most of these genealogies were fabricated to elevate the status of a family. This was common, not only with Gaelic families, but this trend went on in England, France, Spain, etc. For this reason the McCain research is concentration of historical McCains and currently is not looking into the pre late 1300s ancestry of the group. The Recent Ancestral Origins of the McCains indicate that they were native to mid Argyll and there are no striking kinships to any families outside this area. This strongly suggest they were indigenous to mid Argyll.
Many McCains have asked about Gaelic clan affiliations; the nature of society and politics in mid Argyll circa 1450 to 1600 was one of great change and the consolidation of the Camibeul family's control over this area. Most of the McCain lands were 'resigned' over to the Earls of Argyll, who in-turn was also the taoiseach (chief) of the Caimbeul clan. This happened to most of the families in this area, not just to the McCains. The Caimbeul family in turn had interests in east Donegal and sent many families from mid Argyll to east Donegal circa 1570s into the 1590s and the McCains were very likely in this migration.