The ruins themselves are rather unremarkable; a 1942 survey described them as "very insignificant", barely visible amongst the vegetation that has reclaimed the site over the centuries. What you won't spot from ground level, however, is perhaps the most intriguing feature of this forgotten stronghold.

Encircling the former castle grounds is a remarkably well-preserved moat, still clearly defined despite the passage of nearly five centuries since the castle's destruction. This water-filled defensive ditch wasn't merely a standalone feature; archaeological evidence suggests it served a dual purpose, forming part of the defensive bawn system for the nearby Moystown Castle. A bawn was essentially a fortified enclosure, typical of Irish tower houses, designed to protect livestock and provide an outer line of defence.

The Mac Coghlan castle's story is recorded in various historical sources, including Cooke's work from 1875 and O'Flanagan's volumes from 1933, though much of its detailed history remains lost to time. The site was formally documented in the Archaeological Inventory of County Offaly in 1997, with updates added as recently as 2011, ensuring this modest but historically significant ruin isn't entirely forgotten, even if nature has done its best to hide it from view.