Abergairn Castle is finely situated on the summit of an isolated kaim about half a mile west of the upper outlet of the Pass of Ballater, and about the same distance north-east of St. Kentigern's ancient church, near the junction of the Gairn with the Dee. The castle had commanded a magnificent view, now partly obscured to the south-west by graceful birch trees, of Glenmuick and the hills which enclose it, culminating in the grand outline of Lochnagar. Westward and northward the ground rises and hides the valleys of the Dee and the Gairn. To the east and south the kaim sinks abruptly into a wide bottom extending to the mouth of the Pass of Ballater. Through this bottom runs a tiny stream that drains the Pass ; and the flats adjoining its bed are still largely in marsh, so that before modern drainage this must have provided a strong defence for the site.