Known as Island House on 19th and early 20th century Ordnance Survey maps, this rubble limestone structure appears to have grown over time, beginning as a compact tower house before expanding into a more substantial residence. The original northern portion, almost square in plan and tower-like in appearance, likely dates to the late 16th or early 17th century, judging by its defensive gun loops positioned strategically around doorways and windows. This earlier building may have served as a small fortified dwelling during turbulent times when such defences were essential.

The house underwent significant expansion, probably later in the 17th century or early 18th century, when a larger rectangular block was added to create the distinctive T-shaped footprint visible today. The join between old and new construction remains clearly visible in the masonry. The complete structure featured three steep pitched gables, each crowned with a chimney, and multiple storeys supported by timber floors, evidence of which survives in stone corbels and putlog holes. The main entrance shifted to the newer southern block, which contained four bays with regular window arrangements and multiple fireplaces, suggesting a more comfortable domestic arrangement than the defensive original tower. Interestingly, gun loops in what became an internal wall prove that the tower once stood alone, whilst Knox’s 1911 survey revealed that the older portion was built over a roofed culvert that channelled water from a hollow to the west directly into the lake.

Though now roofless and partially ruined, with trees growing within its walls and stone rubble filling the interior, the building preserves remarkable details of its construction and use. The walls stand to their full height despite several breaches, and features like drawbar sockets, wall cupboards, and fireplaces remain visible throughout. Historical records indicate that in the late 16th century, Theobald Dillon purchased these lands from the Mac Costellos, who had maintained a castle here, suggesting this fortified house may have replaced or incorporated elements of an earlier medieval stronghold. The site remains associated with nearby earthworks and a moated enclosure, placing this intriguing structure within a broader landscape of defensive architecture that once protected this lakeside location.