At a small holy well in pasture near Killala, the old belief held that if a fish were seen jumping in the water, a pilgrim's request would be granted; if the fish merely floated, the answer was no. It is a detail that sits somewhere between folk divination and something older and harder to name, and it attaches itself to a pool that is, in physical terms, remarkably modest: a rough drystone enclosure no more than forty centimetres high, surrounding a body of water barely a metre across, fed by a natural spring now channelled into a field drain.

The well appears under the name Toberachrinn on Ordnance Survey six-inch maps from both 1838 and 1929, suggesting it was a sufficiently recognised landmark to be recorded across nearly a century of mapping. Dedicated, according to local tradition, to St. Brigid, it was an active site of pilgrimage into at least the first half of the twentieth century, with stations, the traditional rounds of prayer performed at holy wells and sacred sites, still being observed there within living memory at that time. A hawthorn tree beside the well served as a rag tree, a place where petitioners would leave votive offerings, typically strips of cloth or coins, in the hope of a cure or a favour. The practice of tying rags to trees at holy wells is one of the most persistent expressions of popular devotion in Ireland, pre-Christian in feel even when bound up with Christian saints. Within forty metres to the west-northwest lies a rath, a circular earthwork enclosure of the early medieval period, a reminder that this modest south-facing slope has drawn human attention for a very long time.