These structures are found in their hundreds across Ireland, typically associated with ringforts or early Christian settlements, and their precise purpose has long been debated. Likely uses include food storage, taking advantage of the stable cool temperatures underground, refuge during raids, or some combination of both. The one at Killeens is recorded as a monument, which means it has been formally identified and placed under legal protection, yet the details of its construction, dimensions, and condition remain largely inaccessible through public channels for the time being.

Souterrains were generally built by roofing a trench with large stone lintels, then covering the whole structure over, so that from the surface there may be little or nothing to see. Some are single passages; others branch into multiple chambers with low connecting creeps that would have forced anyone entering to move slowly and in single file, a feature that would have made them defensible as well as functional. In Kerry, the density of early medieval settlement was considerable, and souterrains are a recurring feature of the landscape, often discovered only when the ground above them subsides or when farmwork disturbs the stonework below. Without more specific information about the Killeens example, it is difficult to say whether it was found intact, partially collapsed, or recorded only as a surface feature.