The site is a rath, an earthen ringfort of the kind built across Ireland from roughly the Iron Age through the early medieval period, typically serving as a defended farmstead or the residence of a local lord. What sets this one apart is the combination of its double-bank enclosure and a surviving stone palisade, a feature not commonly recorded at sites of this type, giving it a layered, almost improvised quality that suggests repeated occupation or reinforcement over time.

The fort is roughly circular, measuring 22 metres north to south and 21 metres east to west. Two earthen banks enclose the interior, separated by a deep fosse, the term for the ditch dug between defensive banks, with the inner bank rising 4.3 metres above the base of that fosse. The outer bank, standing around 0.9 metres high, survives along the arc from east-southeast to northwest. Most striking is the stone palisade running from south-southwest to northeast, made up of thirty-five stones, the tallest reaching 2.3 metres. Some stand upright, others have fallen and lie prostrate, arranged in an irregular pattern that gives the line a weathered, organic character rather than the uniform geometry of later construction. Parts of the site are heavily overgrown with vegetation. The fort was recorded in D. Lavelle's 1994 archaeological survey of Ballinrobe and its surrounding district, which catalogued monuments around Lough Mask and Lough Carra.

Inishowen Island lies on the eastern shore of Lough Mask, a large lake straddling the Mayo and Galway border known for its depth and its sudden squalls. Reaching the island requires a boat, and the overgrown condition of the fort means the stones of the palisade reward patient searching rather than immediate recognition. The tallest standing stones, at over two metres, emerge from the vegetation with a presence that is easier to appreciate up close than from a distance.