This flat-topped structure, measuring approximately 20 metres in diameter and standing 2.5 metres high, is likely the remains of a medieval motte; a type of fortification introduced to Ireland by the Anglo-Normans in the late 12th century. The mound’s strategic position above the river would have provided its builders with clear views across the surrounding countryside, whilst the steep 5-metre drop to the water on its southeastern side offered natural protection.

Today, dense brambles and bushes have claimed the site, obscuring much of its original form beneath a tangle of vegetation. Despite this overgrowth, the motte’s distinctive shape remains clearly visible in the landscape. These earthwork castles typically supported a wooden tower or palisade on their summit, serving as both defensive strongholds and symbols of Norman authority as they established control over newly conquered territories.

The motte at Rathosey represents one of many such fortifications scattered across the Irish countryside, silent reminders of a turbulent period when Norman lords carved out estates amongst existing Gaelic kingdoms. Archaeological surveys conducted in 2005 documented this site as part of Sligo’s rich medieval heritage, though no excavations have revealed what structures once crowned its summit or who exactly commanded this riverside stronghold.