Originally the seat of the Nugent family, this Westmeath stronghold was built as a square bawn with four circular corner towers, though only the northwest and northeast towers survive today. The castle appears on the 1657 Down Survey map as an impressive castellated structure, owned at that time by Robert Nugent, who was recorded as an ‘Irish Papist’ during the turbulent period of the Cromwellian conquest. Sir Thomas Nugent, who founded this branch of the family line, was the second son of Richard, seventh Baron of Delvin, establishing Carlanstown as a distinguished seat of this prominent Anglo-Norman dynasty.

The defensive bawn wall still encloses much of the site, incorporating fascinating architectural details that hint at the castle’s evolution through the centuries. A particularly striking feature is the tall rectangular chimney stack projecting from the western wall, marking where the 17th century house once stood in the southwest quadrant. Adjacent to this, the quoins of the original castle’s northwest angle can still be spotted rising above the bawn wall, whilst a semi-circular tower at the southern end features a horizontal gun loop that extends into the adjoining wall section. The ornate square-headed doorway on the west side, decorated with scroll brackets and likely dating from the late 17th or early 18th century, may have been salvaged from the original castle structure.

By the early 19th century, the medieval stronghold had given way to more peaceful purposes. Around 1800, Carlanstown House was constructed along the line of the demolished southern bawn wall, possibly incorporating fabric from the earlier structure. The Duke of Buckingham later improved the property, creating what was described in 1837 as a ‘good farm-house’ on the site of the old mansion. Today, the three-bay Georgian house stands alongside post-1700 farm buildings that occupy the southern half of the bawn area, creating an intriguing palimpsest where defensive walls now shelter agricultural outbuildings rather than armed retainers. The site was extensively documented in 1864 by artist and antiquarian George Victor Du Noyer, whose detailed sketches and architectural drawings provide valuable insights into the castle’s appearance before further deterioration.