A souterrain is an underground stone-lined passage or chamber, typically constructed during the early medieval period in Ireland, roughly between the sixth and twelfth centuries. They were built adjacent to settlements, often beneath or beside ringforts, and served most likely as cool storage spaces, places of refuge, or both. The one at Knockanush is known to exist and has been assigned a monument record, but detailed published information about its form, dimensions, and condition remains sparse.

Kerry has an unusually dense concentration of souterrains, a reflection of the county's dense early medieval settlement pattern and the ready availability of stone suitable for dry-stone construction. Many Kerry souterrains consist of long, low passages with corbelled or lintelled roofs, occasionally opening into wider chambers. Without specific survey data for the Knockanush example, it is difficult to say more about its particular character, how many chambers it contains, whether it has been excavated, or what its relationship to any associated settlement features might be. What the record does confirm is that the monument exists and has been identified as part of the broader archaeological landscape of this part of Kerry.

For anyone with a serious research interest in the site, the formal record is held in archive rather than currently available through public digital sources, which itself says something about how many of Ireland's lesser-known monuments are still waiting for their documentation to catch up with what the ground has preserved.