The castle is believed to have been constructed by the Browne family of Mulrankin, though by 1641 it was already recorded as being ‘in ruins’ whilst still in the possession of William Browne, who held it alongside 500 acres of land in Brownswood and Crefoge. Today, only fragments of the eastern and southern walls remain, rising to what would have been the second storey, offering visitors a glimpse into its original imposing presence.

The surviving architecture reveals fascinating defensive features typical of its era. The ground floor retains its vaulted ceiling, complete with a lintelled alcove at the southeast corner that once housed three gun loops; strategic openings that allowed defenders to fire upon approaching enemies. A damaged embrasure in the eastern wall contains two additional gun loops, whilst the first floor conceals a rather grim feature: an oubliette built into the masonry of the vault at the southeast angle, with a single gun loop positioned in the wall above. This bottle dungeon, accessible only from above, would have served as a particularly unpleasant prison cell for unfortunate captives.

Despite centuries of decay, several architectural details persist in telling the castle’s story. Two corbels that once supported the first floor ceiling still project from the eastern wall, whilst fragments of window embrasures can be traced at the second floor level in both the eastern and southern walls. These remnants, documented in the Down Survey parish maps of 1656 to 1658, help archaeologists piece together the castle’s original layout and understand how the Brownes and their household would have lived, defended, and ultimately abandoned this riverside stronghold.