 Clan Maclachlan , also known as Clan Lachlan and Clann Lachlainn , is a Highland Scottish clan that historically centred on the lands of Strathlachlan on Loch Fyne , Argyll on the west coast of Scotland . The clan claims descent from Lachlan Mor , who lived on Loch Fyne in the 13th century , and who has left his name upon the countryside he once controlled : places such as Strathlachlan , Castle Lachlan and Lachlan Bay . Tradition gives Lachlan Mor a descent from an Irish prince of the O 'Neill dynasty , Ánrothán Ua Néill , son of Áed , son of Flaithbertach Ua Néill , King of Ailech and Cenél nEógain , died 1036 . Clan Maclachlan has been associated with other clans , such as Clan Lamont , Clan Ewen of Otter , Clan MacNeil of Barra , and the MacSweens : as all claim descent from Anrothan O 'Neill who left Ireland for Kintyre in the 11th century . From this descent the clan claims a further descent from the legendary Niall Noigíallach , High King of Ireland , who lived from the mid 4th century to the early 5th century . 
