Located on the seabed at Doonierin, just off the southern shoreline of Drumcliff Estuary, is St. Colmcille’s Well, named for the saint associated with Drumcliffe Monastery which was located nearby. One of several such holy wells in the locality, this one is unique in that it is only visible, and accessible, at low tide and consists of a low seaweed covered wall one or two stones high. It is traditionally visited by pilgrims on the 9th of June, St Colmcille’s feast day, or Pattern Day, as its waters is believed to be a curative for a range of ailments.

The roadway at Doonierin marks the location of an ancient causeway (togher in Irish) across Drumcliffe Estuary that was for centuries a traditional and strategic crossing point on the Sligo-Donegal route. It was because of its strategic value that several battles were said to have occurred in this area, to include the Battle of the Books which took place on the northern side of the estuary, closer to the slopes of Benbulben.