Not medieval, not post-medieval, not modern; simply indeterminate. That classification, vague as it sounds, is itself a kind of statement. It means that whoever recorded the structure could not place it with confidence in any known period, leaving it suspended between centuries without a name or an era to anchor it.

Tomnahulla is a small rural townland in Galway, and the house recorded there carries none of the usual markers that allow surveyors to pin a building to a particular age. Stone construction can outlast its context, and without dateable finds, documentary evidence, or distinctive architectural features, a structure can resist even careful scrutiny. The designation of indeterminate date is not a failure of archaeology so much as an honest acknowledgement that some buildings simply do not give themselves away. It may be a vernacular dwelling of the eighteenth or nineteenth century, or something considerably older; without further investigation, the question stays open.