Sundrum Castle is located 1.5 kilometres north of Coylton. It was originally built in the 14th century for Sir Duncan Wallace, Sheriff of Ayr, and considered one of the oldest inhabited castles in Scotland. Long-term owners included the Cathcart family, and the Hamilton family, who expanded it the 1790s, incorporating the original keep into a mansion.
It was further expanded in the early 20th century by Earnest Coats. For a time it was then a hotel, though fell into disrepair. After extensive renovations in the 1990s, it was split into multiple privately owned properties. The Sundrum estate now also includes a holiday park.
The castle is split into three separate properties, consisting of the original tower keep, and separate Georgian and Victorian wings, each with their own style.
References:Sigmaringen Castle was first mentioned in the year 1077 in the chronicles of Petershausen monastery. The oldest parts of the castle are concealed beneath the alterations made during the 17th and the 19th centuries. The secret of the earliest settlement built on this defendable rock will never be fully revealed: large-scale excavation work would be necessary, which the extensive land development renders impossible. Judging from the many Roman remains unearthed in the area around Sigmaringen, the 12th century keep known as the 'Roman Tower' could be traced back to a Roman predecessor.
The castle remains that have been preserved (gate, great hall and keep) date back to the Staufer period around 1200. The castle remains were integrated into subsequent buildings. The foundations of the castle buildings are to a large extent identical to the surrounding castle wall.
These remains give us a good idea of how the castle might have looked during the 12th century.