It appears on the archaeological monument record without a period, without a name attached to its builders, and without any description of what survives above ground. That absence is itself worth pausing over. Most recorded structures can be placed, however roughly, within a century or a broad historical phase. This one cannot, or at least has not been yet.

Achill has been inhabited for thousands of years, and Keel in particular sits close to the remains of earlier settlement, from promontory forts along the cliffs to the remains of a lazy-bed landscape that speaks to the catastrophic losses of the Famine decades. A house recorded simply as "indeterminate date" could belong to almost any layer of that long occupation. It might be the remnant of a pre-Famine clachan, a cluster of interconnected dwellings once common in the west of Ireland, or it could be something considerably older, its stonework too ambiguous or too eroded to assign with confidence. Without further detail it is impossible to say, and the honest position is that this particular structure has not yet been fully examined or described in any accessible public record.