Originally built as a "late 12th- or early 13th century defensive motte"[1] it provided protection for Starny Keppie Harbour and Rattray village.

[5] Originally situated on "a rock near the sea",[6][7] Castlehill is today about 1 mile inland as shifting sands have significantly altered the shape of the coast.

Located to the south of Loch Strathbeg it can be seen as a grassy "circular mound"[8] which is "oval & natural with its top slightly dished".

The first construction of Castlehill was a small keep during the late middle ages, or a 12th century "timber castle or Motte"[4] built to protect the estuary.

He is known to have completed a "manor house"[4] with "a fine timber-framed hall"[4] (the castle) which was accompanied by the private St Mary's Chapel which he constructed "a quarter of a mile"[10] (0.4 kilometres) south, in Rattray village itself.

The destruction of the stone castle and the nearby village of Rattray, is said by "a tradition"[7] to have happened during the great storm of 1720[18] which cut off Strathbeg Bay.

Today there is not much to be seen at the site as the remains have "for a long period [been] covered with a deep soil, and now- the swords of the warlike house beaten literally into ploughshares".

"[20] Items recovered include; "a quantity of regularly-laid stones were removed c. 1734 and some silver coins"[5] as well as two kilns stands found in 1829 (today held in Marischal Museum, Aberdeen).

[21] In 1740 "a man who drove his spade through the panel of a door was immediately suffocated"[7] having got caught in the sand and at an unknown date, a "well-made causeway was discovered at the foot of the mound under which the Castle is said to be buried.