The following genealogy is taken from a text within the O Clery Book of Genealogies  a genealogical collection compiled in the seventeenth century as updated by genealogical information extracted from various later sources. The additions from the later sources are highlighted. Names have been standardised.
Aibhne | Niall | Torlach |_______________________________________ | | Brian Eoghan | | Domhnall Diarmaid | | Eoghan Diarmaid |________________ |______ | | | | Donncha Domhnall Aine 4 others |________ |_______________ | | | | | Annraoi Brian Eoghan 2 sons Seoirse
These are the only gateways back into the medieval MacLochlainn of Inishowen genealogy that are ever likely to be found. The descent from Domhnall son of Brian appears in an Exchequer bill of 1732  while the descent from Diarmaid son of Eoghan appears in a confirmation of arms of 1702 . These lineages remain traceable because in the first instance a family conformed to the protestant Anglican state church and became involved in a lawsuit whose papers were deposited in state archives while in the second instance a family exiled in France had their confirmation of arms recorded into state archives as a proof of nobility. The lineages of all other MacLochlainn families have been rendered untraceable in the record by reason of their obscurity with the exception of a fragmentary seventeenth century lineage of a father and son associated with lands along the Keenaght river in Malin . Names have been standardised.
Emann | Aedh
We have to wait two hundred years until the mid-nineteenth century for the general recording of MacLochlainn of Inishowen genealogical events to resume in the form of better-surviving Catholic parish registers and the introduction of civil registration of all births, marriages and deaths. We should remember at this point that the MacLochlainn of Inishowen genealogy only survives to us in written form because of their former prominence and that the genealogy of the general mass of the population had always passed unrecorded. The memorialisation of the MacLochlainn genealogy ceased in the seventeenth century upon their displacement by an incoming class of protestant English and Scottish landowners having great pretensions but whose lowly origins are betrayed by their somewhat truncated entries in peerage and landed gentry publications such as Burke's. Only those prominent natives who aligned themselves with this new class appear in the eighteenth century record in Ireland. Only those who appear in sufficient depth in the eighteenth century record can have their genealogy reconstructed. Such is the barrier that we face. The only significant conformity of which I am aware concerns a single family traced in the Exchequer bill of 1732 who descend from a person who converted to the protestant Anglican state church and eventually became Anglican rector of the parishes of Clonmany, Donagh and Desertegney in 1672 . This family descends from the former chiefly branch and can be traced from Kinnagoe Bay into Clonmany and from there into Desertegney upon the appointment of one of their next generation to the Anglican rectory of that parish in 1716 . There they become visible as the only MacLochlainn households in the whole of Inishowen to appear in the 1740 Protestant Householders List  though by the time of the first surviving census they have reverted to Catholicism. This is all a great deal more than can be said for the family exiled in France. These descend by a different route from the former chiefly branch and claimed a titular chiefship in exile but soon after 1713 they become untraceable in the French record  and are lost to history.
When tracing an ascent back from the present the researcher should beware of ignoring the countless lines that have been lost to obscurity in favour of homing in on these few highly visible gateways. Unfortunately the dearth of eighteenth century records relating to the general population in Ireland will tend to ensure that only a vanishingly small number of people will ever be able to document a MacLochlainn of Inishowen ascent much beyond 1800.