Now owned by the IDA in an area designated for industrial development, this site preserves layers of history from a 16th-century tower house to an 18th-century mansion. The oldest surviving structure, a two-storey rectangular building near the southwest corner, appears to be the remains of the original tower house, though much altered over the centuries. Its ground floor features a wicker-centred barrel vault, whilst modified window openings pierce the eastern and southern walls. Running south from this tower, fragments of the old bawn wall survive, complete with a gun-loop; a testament to the defensive nature of the original fortification.

The most substantial remains belong to a late 16th or early 17th-century two-storey structure that forms the southern side of the complex. This building, measuring approximately 17.65 metres east to west, was later adapted as domestic quarters when Castle Warren house was built in 1796. The ground floor contains a large fireplace in the western wall with a brick-domed bread oven, whilst the first floor boasts two fireplaces, one featuring dressed stone lintels on projecting corbels with chamfered edges. Perhaps most intriguing are the corner bartizans; at the southeast corner, a door with a pointed arch leads to a bartizan supported by five tapering corbels, its roof formed from overlapping corbelled slabs. The 18th-century house itself, built partially over the lower courses of the bawn wall, presents a five-bay, two-storey front with a shallow central breakfront, though its hipped roof has now collapsed and the northeast corner has given way.

The de Cogan family built this castle, reputedly under Richard de Cogan, lord of the manor in 1536. The family held the site until 1642, when the garrison of forty men surrendered to Lord Inchiquin after artillery was brought to bear against the walls; remarkably, 1,000 barrels of wheat were discovered within the castle during its capture. Among the more curious artefacts associated with the site are a carved human head, described in 1915 as a ‘defaced mailed head’, which was sold from the site in the 1920s, and a possible sheela-na-gig discovered in the early 19th century but which disappeared shortly afterwards. Today, the complex stands as a palimpsest of Irish history, its walls bearing witness to centuries of construction, adaptation, and slow decay.