Castle Lachlan lies on the eastern shore of Loch Fyne, near Newton. According to the Clan Maclachlan Society website, the original castle dates back to the 13th century. The original castle was later replaced in the 15th century with the keep or tower that today is in ruins. The ruinous castle lies about 70 feet (21.3 m) north to south, 54 feet (16.5 m) east to west, and at its highest point 43 feet (13.1 m) feet high.

Castle Lachlan lies on the eastern shore of Loch Fyne, near Newton. According to the Clan Maclachlan Society website, the original castle dates back to the 13th century. The original castle was later replaced in the 15th century with the keep or tower that today is in ruins. The ruinous castle lies about 70 feet (21.3 m) north to south, 54 feet (16.5 m) east to west, and at its highest point 43 feet (13.1 m) feet high.