Though the castle was demolished in 1960, its story lives on through historical records and archaeological surveys. The site, now marked only by stonier ground amongst the pasture, held structures that spoke to centuries of Irish fortification and domestic life.

According to late 19th-century accounts by McDix, Colmanstown Castle comprised two main structures: an impressive gateway or barbican, and a square tower house that rose three storeys high. The gateway featured two substantial pillars supporting a broad arch, whilst a single pier from this entrance survived until the early 1970s, when local historian Healy documented it before its final disappearance. The tower house itself was a typical example of Irish medieval architecture, with a barrel vault covering the ground floor; a practical design choice that provided both structural support and fire resistance for the upper levels.

The interior of the tower house revealed the everyday details of castle life through its remaining features. The first and second floors contained fireplaces for warmth and cooking, along with built-in wall presses that served as storage cupboards; common conveniences in medieval Irish tower houses. The walls were plastered, suggesting a level of comfort and refinement within these defensive structures. Today, nothing remains visible at ground level, leaving only historical records and the slightly raised, stony earth to mark where this piece of Dublin’s medieval heritage once stood.