It is a souterrain, a type of artificial underground structure built during the early medieval period in Ireland, typically consisting of one or more chambers connected by low, narrow passages and constructed from dry-stone walling with large capstones across the top. They are found across the country in considerable numbers, yet their precise function remains a matter of ongoing discussion among archaeologists. Theories range from food storage and refuge to ceremonial use, and the answer likely varied from site to site.

The souterrain at Woodfield is registered as an archaeological monument, placing it within a broader landscape of early medieval activity that characterises much of the west of Ireland. Galway's interior and coastal areas preserve a significant concentration of such structures, often associated with ringforts, the circular enclosed farmsteads that were the dominant settlement form of the period roughly between the fifth and twelfth centuries. Whether the Woodfield example is linked to such a settlement nearby is not currently documented in publicly available records, and the specific details of its construction, dimensions, and condition remain inaccessible without further archival research. That gap itself is telling. Many souterrains across Ireland were discovered incidentally, when farmland was being ploughed or drainage work disturbed the ground, and a good number remain only partially investigated.