On a low hillock in the grassland of Castlebin in north County Galway, there was once a circular enclosure roughly thirty metres across. It was recorded on Ordnance Survey six-inch maps, plotted and measured, and for a time at least it was legible in the landscape. Today, a silage pit occupies the spot, and no visible surface trace of the monument survives.

Circular enclosures of this kind are among the most common archaeological features in the Irish countryside. They are the remains of enclosed settlements, typically of early medieval date, though some are older, defined by an earthen bank or fosse that once surrounded a homestead or small community. At Castlebin, the enclosure sat on a hillock adjacent to a townland boundary, which is itself a detail worth noting. Townland boundaries in Ireland are extraordinarily ancient, and their lines often follow or respect earlier features in the landscape, suggesting the enclosure was already a landmark when those divisions were being drawn or maintained. What the enclosure once contained, who lived within it, and when it fell out of use, the available record does not say.