You may see different dates for the building of Cadzow Castle. The most common misconception is to term it a 16th-century castle, but this refers only to the rebuilding of Cadzow by Sir James Hamilton of Finnart for his half-brother the 2nd Earl of Arran.
Sir James rebuilt the early medieval structure, creating a more comfortable fortified manor, befitting the more settled times. Mary, Queen of Scots briefly stayed at Cadzow in 1568 after her escape from Loch Leven Castle.
The castle was besieged and sacked in 1572 by the Protestant Regents who were administering Scotland during the minority of James VI. Cadzow was destroyed by explosives to render it useless for military purposes and left to crumble into ruin until the 10th Duke of Hamilton began a rebuilding programme in 1820.
The Duke intended Cadzow to become a romantic folly in the grounds of nearby Hamilton Palace. The earlier ruins were landscaped to present a picturesque ruin in keeping with the romantic ideals of the time.
Today, the Great Hall, Kitchen, and Chapel remain from the medieval buildings at Cadzow. The site is defended by a pair of drum towers, one partially sunk in the ditch.
NOTE
Cadzow Castle has suffered enormously from erosion and neglect over the past few years. Historic Environment Scotland (formerly Historic Scotland) who administer the site, have fenced it off behind high fences and the crumbling masonry walls are covered with scaffolding and almost overwhelmed by undergrowth.
Signs you can read through the fence say that the castle walls are dangerously unstable and the scaffolding is temporary and part of a necessary programme of work to stabilise the ruins. While that ambition is totally understandable, it does seem that the scaffolding has been untouched for years, while it rusts in place and is itself half-submerged beneath the encroaching foliage.
Cadzow today gives off a sad air of neglect. Hopefully, both funds and ambition can be found to repair the walls and once more give visitors access to the site.
You can get a good view of the castle from the terrace walk outside Chatelherault's West Lodge and visitor centre, and there is another good view from the Duke's Bridge, below the castle. A signposted footpath leads directly past the fenced area, and you can get a sense of how impressive the fortifications once were.
The castle is easy to find. Chatelherault Country Park is extremely well signposted from major roads near Hamilton, including the M74. Within the park, the castle is extremely well signposted and is a short 6-8 minute walk from the West Lodge visitor centre.