Auchans Castle is a mock military mansion, Category A listed, T-plan building of a late 16th-century date converted to the L-plan during the early-to-mid-17th century; its ruins stand about 1 km of Dundonald, South Ayrshire. It was held at various times by the Wallace, Cochrane and Montgomerie families.
The now greatly ruined castle stands in its woodland policies amidst a series of stone-walled parks, the walls of which are mainly in a state of collapse. The building and the park walls were in the main constructed using stone robbed from Dundonald Castle. A vast number of valuable Eglinton family papers were discovered in one of the apartments in the 1880s, rescued as the building was in a terminal state of decay. Many had already been destroyed through neglect.
First record of Kastelholma (or Kastelholm) castle is from the year 1388 in the contract of Queen Margaret I of Denmark, where a large portion of the inheritance of Bo Jonsson Grip was given to the queen. The heyday of the castle was in the 15th and 16th centuries when it was administrated by Danish and Swedish kings and stewards of the realms. Kastelhoma was expanded and enhanced several times.
In the end of 16th century castle was owned by the previous queen Catherine Jagellon (Stenbock), an enemy of the King of Sweden Eric XIV. King Eric conquered Kastelholma in 1599 and all defending officers were taken to Turku and executed. The castle was damaged under the siege and it took 30 years to renovate it.
In 1634 Åland was joined with the County of Åbo and Björneborg and Kastelholma lost its administrative status.