About Dalhousie Castle: It is difficult to imagine a building which now stands peacefully along the River South Esk amongst the rolling Midlothian countryside, has experienced such a varied and turbulent past. Dalhousie Castle dates back to the 13th Century and was originally built by the Ramsays of Dalhousie, a noble Scottish family descended from Simundus de Ramseia, who in about 1140 followed King David I to Scotland from the Huntingdonshire village of Ramsay.