What survives today is merely the western end of what was once a formidable three-storey stronghold, including a southwestern turret and a partially collapsed northwestern stair turret cloaked in ivy. The structure, built from squared blocks with roughly dressed quoins and a defensive base batter, witnessed one of its most dramatic moments in 1642 when it became the battleground for a major engagement between Royalist forces under Lieutenant General Byrne and Parliamentarians commanded by Sir Charles Coote.

The southwestern turret, measuring approximately 2.65 by 2.3 metres internally, features a vaulted ceiling constructed using wickerwork centering; a medieval building technique rarely seen in surviving structures. Access is through a short passage, whilst the interior is illuminated by a narrow slit opening in the western wall. The main chamber once boasted a vaulted ceiling with a segmental arched opening in the south wall, and traces of springing for an arch remain visible on the western wall. A large wall press occupies the northwestern side, whilst the remains of the stairwell in the northwestern turret still show evidence of the slit openings that once provided light to those ascending the stairs.

Time and weather have not been kind to Castlefarm; the harsh winter of 2010 reportedly caused some collapse, and the western window opening now teeters on the brink of failure. Victorian accounts from 1897 paint a picture of a more complete structure, describing three storeys with multiple windows, a circular chamber on the first floor complete with wall presses, and large windows in the northern and eastern walls. Today, the ground falls away sharply about five metres west of the tower, possibly marking the line of a former bawn, whilst an associated field system defined by drains and scarped banks extends westward, hinting at the broader medieval landscape that once surrounded this embattled tower.