According to Clare County Library, Deer Island, or Innismore, is situated near the western bank of the River Fergus about a quarter of a mile from the village of Ballynacally.

Administratively it is part of the District Electoral Division of Ballynacally.

Samuel Lewis reported that "Flax was formerly cultivated here… but is now only partially grown".

He also mentioned "some vestiges of an abbey still remaining, founded… at a very early period, by Saint Senan of Inniscattery, who appointed St. Liberius one of his disciples, to preside over it".

The ruins of the old church, some cholera graves and a holy well called Tobar Breedia are still to be seen.