What makes Beanlassa Fort a little unusual is not its basic form, which follows the familiar circular plan of thousands of Irish raths, but the detail preserved in its earthworks. The interior measures roughly 32 metres north to south and 30 metres east to west, enclosed by an inner bank that still rises up to three metres on its outer face. Between that inner bank and a partial outer bank runs a fosse, a defensive ditch, whose base varies between one and a half and nearly three metres wide. The outer bank itself only partially survives, running from the east-southeast to the northwest, while the fosse is best preserved from the southwest around to the north. A three-metre entrance gap cuts through the inner bank at the south.

Ringforts of this kind were built and occupied primarily during the early medieval period, roughly from the fifth to the twelfth century, and served as enclosed farmsteads for families of varying social rank. The double-bank arrangement at Beanlassa, with an inner bank, an intervening fosse, and traces of an outer bank, suggests a more substantial enclosure than the single-bank examples that make up the majority of surviving sites. Close by, approximately 155 metres to the southeast, lies a fulacht fia, a type of ancient cooking site typically identified by a horseshoe-shaped mound of fire-cracked stone and charcoal, usually associated with Bronze Age activity. The proximity of the two monuments does not necessarily mean they were in use at the same time, but it does point to a landscape that saw repeated, layered human occupation across many centuries.