Most carry at least a few markers of their religious significance, a carved stone, votive offerings, a pattern day still observed by local people. The holy well at Letter in County Offaly has almost none of this. What survives is a poorly preserved structure with dry-stone walling on one side only, the facing on the other sides either collapsed or never completed, and no further visible features to speak of. It is, by most measures, a quiet and easily overlooked site, yet its association with an early Irish saint gives it a history that extends well beyond its modest physical remains.

The well is dedicated to St Lugna, a figure recorded in connection with this part of Offaly by the scholar O'Flanagan in 1933. Early Irish saints of this kind were often the focal points of small monastic communities, and the presence of a church immediately to the south-east of the well fits a familiar pattern from early medieval Ireland, where a holy well and an ecclesiastical site occupied the same ground, each reinforcing the sanctity of the other. The church at Letter would have given the well its ritual context, and the well in turn marked the landscape as one associated with a particular saint's spiritual territory.