Perched atop Croaghan Hill in County Donegal sits an ancient hillfort that once commanded views across the historic territory of Magh Itha. This roughly circular enclosure, measuring about 85 metres across, is defined by the remains of a collapsed stone wall that tells different stories depending on where you stand. In some sections, the grass-covered wall rises to an impressive 5 metres wide and 1 metre high, while in other places it's barely visible, having melted back into the landscape over centuries. A more recent field boundary has cut through the western side, making the wall's outline particularly vague in that area.

The most striking feature within this ancient fortification is a passage tomb near its centre; a substantial mound measuring 21 metres in diameter and rising 3 metres high. The enclosure itself shows signs of careful construction, with what appears to be an original entrance on the southeast side, marked by deliberately placed stones lining the gap. Throughout the interior, natural rock outcrops break through the surface, creating a rugged terrain that would have been part of the site's defensive character.

This monument has been recognised as nationally significant and is protected under a preservation order from 1987. The hillfort's strategic position on the summit gave its inhabitants control over an extensive area, making it a crucial site in understanding how ancient communities organised and defended their territories in prehistoric Ireland. The site was documented in the Archaeological Survey of County Donegal in 1983, which catalogued field antiquities from the Mesolithic period through to the 17th century.