Glamis Castle is set in the wide valley of Strathmore , near Forfar , the capital of Angus . It lies between the Sidlaw Hills to the south and the Grampian Mountains to the north , approximately 20 kilometres from the North Sea . Glamis is set in the broad and fertile lowland valley of Strathmore , near Forfar , county town of Angus , which lies between the Sidlaw Hills to the south and the Grampian Mountains to the north , approximately 20 kilometres inland from the North Sea .