By 1536, it served as a stronghold for the Costelloe family, before passing into the hands of Lord Viscount Dillon of Castlerea and Gallen by 1635. Today, nothing remains visible above ground in the pastoral landscape, though the site sits just 130 metres west of Kilcolman church, positioned on low-lying ground near a northwest to southeast running stream that once flowed south of the castle.

Archaeological excavations in 1950 revealed the castle’s footprint: a rectangular earthen platform measuring 29 metres north to south and 27 metres east to west, rising 1.5 metres high. The excavation uncovered a substantial perimeter wall, 2 metres thick with an outer base batter, surrounded by a defensive fosse 6 metres wide. The western side featured a now-destroyed entrance and causeway. While several archaeological investigations between 2003 and 2006 in the surrounding area yielded no related materials, testing conducted directly on the monument in 2012 proved more fruitful.

The 2012 excavation uncovered a 2.8-metre section of base batter belonging to what appears to have been a turret approximately 3.5 metres in diameter, along with cairn material. These findings suggest the castle was more architecturally complex than the simple rectangular platform might indicate, possibly featuring defensive towers at strategic points along its walls. Though the castle itself has vanished from view, these archaeological traces continue to tell the story of this once-important medieval fortification that stood guard over the Roscommon countryside for centuries.