What remains today is a fragmentary L-shaped house, standing two storeys tall in places, though its western end has completely collapsed into rubble. The eastern wing fares better, remaining largely intact except for damage to the central portion of its south wall. A remnant of the castle’s defensive bawn wall, measuring 1.5 metres thick, extends from the northeastern corner, whilst the eastern gable shows signs of a slight base batter; a defensive architectural feature common to fortified houses of the period.

This appears to be a seventeenth-century fortified house, originally protected by bawn walls to the north and surrounded by landscaped gardens to the south, as shown on early Ordnance Survey maps. The construction is notably austere, lacking any cut stone embellishments in its windows, fireplaces or doorways; all featured flat tops supported by wooden lintels rather than the stone arches found in grander structures. The Civil Survey of 1654-6 paints a picture of early decay, describing it as ‘a castle (ye walls onely standinge) with a bawne and two thatcht houses’, suggesting the main structure was already in ruins by the mid-seventeenth century.

The castle’s last recorded proprietor before its decline was Marcus maGrath, who held the property in 1640. John O’Donovan, the renowned Irish scholar, documented wall footings of what he described as a modern building protruding from the eastern gable during his nineteenth-century surveys, though these additions have since disappeared. Today, Blean Castle stands as a modest but evocative reminder of the network of smaller fortified houses that once dotted the Irish countryside, built by landowners who needed defence but lacked the resources for grand castles.