The old settlers seem to have congregated at the southwest corner round the beautiful little harbour of Portdoon, where there is ample archeological evidence of their presence. The ancestry of the current population includes Wicklow, Wexford and Galway. Some of the dominant names include ÓToole, Heanue and Concannon, names from Leinster, Ulster as well as the nearby Connemara Gaeltacht.
Geologically Inishturk dates from the Ordovician period. Two separate folds of schists and shales rise out of the
Atlantic to form Inishturk, which is a continuation of the same folds as Croagh Patrick on the Mayo mainland.