What makes the site at Knockalinsky unusual is that it consists of two such enclosures placed side by side, their banks meeting at shared points to the north and south, forming a figure-of-eight arrangement across the top of a low rise in County Mayo. The northern enclosure measures roughly 50 metres north to south and 41 metres east to west; the southern is only slightly smaller at 46 by 43 metres. Together they suggest a settlement of some complexity, perhaps housing two related households or serving distinct domestic and agricultural functions within a single defended compound.

A ringfort, sometimes called a rath, is essentially a circular area of land enclosed by one or more earthen banks, the standard form of rural settlement in Ireland from roughly the fifth to the twelfth centuries. At Knockalinsky, the banks incorporate many large boulders, which would have added both mass and stability to the earthworks. To the north-east and west of the southern enclosure, an external fosse (a defensive ditch) and an outer bank still survive, indicating that the southern enclosure at least was given an additional layer of defence. More intriguing still is the possible souterrain within the northern enclosure. A souterrain is an underground passage or chamber, typically stone-lined, used for food storage or concealment in times of danger. Its presence here, if confirmed, would point to a settlement that was both well-organised and aware of the need for security. The earthen banks across the whole site are now heavily overgrown, and the site sits in pasture, grazed and quietly ageing in the landscape of south Mayo.