Scheduled Monument

Scrabster CastleSM2630

Status: Designated


Where documents include maps, the use of this data is subject to terms and conditions (

The legal document available for download below constitutes the formal designation of the monument under the Ancient Monuments and Archaeological Areas Act 1979. The additional details provided on this page are provided for information purposes only and do not form part of the designation. Historic Environment Scotland accepts no liability for any loss or damages arising from reliance on any inaccuracies within this additional information.


Date Added
Last Date Amended
Supplementary Information Updated
20th Century Military and Related: Pillbox, Prehistoric domestic and defensive: settlement (if not assigned to any more specific type), Secular: castle
Local Authority
ND 10670 69120
310670, 969120


The monument comprises the remains of Scrabster Castle, alternatively known as Bishop's Castle or Bishop's Palace, which is visible today as an earthwork and upstanding ruin. The scheduled area also includes the remains of prehistoric settlement and World War II defences. Scrabster Castle was originally scheduled in 1967, but the area was inadequate to protect the full extent of the monument: the present re-scheduling rectifies this.

The castle is situated on a low coastal promontory roughly midway between Scrabster and Thurso, SW of Neb Point. It faces NE and would have dominated Thurso Bay, a broad, sheltered natural harbour surrounded by flat to gently sloping fertile land. Today the castle is visible mainly as the turf-covered remnants of stone walls standing up to 3m high, sited on a large lozenge-shaped mound about 8.7m high. The castle is protected by Burnside Burn on the W and a wide ditch to the S. In all, the castle must have measured approximately 45m NE-SW by 30m transversely.

The castle was not the first use of this site. During trial excavations in 1971 and 1973 Iron Age pottery was found beneath the cobbled path, together with a stone-lined box interpreted as a possible water tank, such as is often found in the interior of brochs or roundhouses. In addition, in the cliff section there is evidence of middens beneath the castle wall foundations, which would also suggest that this site was occupied in prehistoric times.

Scrabster Castle is clearly medieval in date but, given the absence of more precise dating evidence, it cannot be positively identified as the 'borg at Skarabolstad' mentioned in Orkneyinga Saga (written in Iceland in about 1196), where Earl Harold of Orkney mutilated Bishop John. It is first recorded as Scrabster Castle in 1328 in relation to a fee owed to the chamberlain of Sir Robert of Peblis. Gilbert Mudy was granted the keeping of the castle of 'Scarbestoun' by his brother William, Bishop of Caithness, in 1455. In about 1544 it was seized by the Earl of Caithness, who was later appointed the constable of the Castle of Scrabster by Bishop Robert in 1557. The last record of a bishop's residence here dates to 1566, and in 1726 it was described as being 'wholly ruinous'. Today, the enclosure walls and tower foundations are at considerable risk of further deterioration due to erosion.

The curtain-walled castle had a square tower at its NE extremity, with perhaps two or three ranges of buildings within the courtyard walls. The main entrance was most probably on the SE with the principal accommodation between this and the tower. The walls of the kitchen range, with open hearth, fireplace and oven, survive to a maximum height of around 2m in the NW corner of the site. These ranges may date to the 13th century, at which time a cobbled path led from the main entrance to the tower. In the 15th century a small range of three rooms was added to supplement the NE range. A small triangular-headed window with dog-toothed mouldings survives from the site, built into an outbuilding at Scrabster House.

The vulnerability of the North Sea coast was recognised during the early part of World War II, when it was reinforced with a complex of coastal defences: pillboxes, anti-tank blocks and gun emplacements. A 1940/41 Type 24 pillbox survives to full height on top of the castle tower. Built of reinforced concrete with clay brick shuttering, it is roughly hexagonal in plan, measuring 4.8m by 4.4m. The door is centrally positioned on its SW face and the interior contains a concrete slab gun table. There is a line of contemporaneous anti-tank concrete blocks along Burnside Beach to the SE, one of which displays '7-10-40' and '14/10/40' graffiti.

The area proposed for scheduling comprises the remains described and an area around them within which related archaeological material may be expected to survive. It is bounded by Burnside Burn to the W, the cliff-edge to the NE and a modern fence line to the S. It is highly irregular in plan with maximum dimensions of 94m NE-SW and 89m WNW-ESE, as marked in red on the accompanying map.

Statement of National Importance

Scrabster Castle is of national importance because of its potential to contribute to our understanding of domestic and defensive architecture and economy in the early medieval period in northern Scotland. Its historical associations and its early date of abandonment contribute to its high archaeological potential, and the castle's association with the powerful Bishops of Caithness adds to its historical significance. The site also has the potential to elucidate the nature of prehistoric settlement and economy. Finally, the site is also of importance because it includes a good example of World War II coastal defences.



The monument is RCAHMS number ND 16 NW 3 (Thurso, Burnside, Scrabster Castle), ND 16 NW 4 (Thurso, Bishop's Bridge) and ND 16 NW 183 (Scrabster Castle pillbox and anti-tank blocks).


Craven, J. B. ed. (1886) Journals of the Episcopal visitations of the Right Rev. Robert Forbes M A of the dioceses of Ross and Caithness and of the dioceses of Ross and Argyll, 1762 and 1770, with a history of the Episcopal church in the diocese of Ross, chiefly during the 18th century and a memoir of Bishop R. Forbes, London, 128.

Craven, J. B. (1908) Diocese of Caithness, 17-21.

County Name Book (1872) Original Name Books of the Ordnance Survey Book, No. 11, 88-89.

Defence of Britain database,, S0013623 & S0013734.

Macfarlane, W. (1906-08) Geographical collections relating to Scotland, Mitchell & Clark eds., 3 vols, Edinburgh, Vol. 1, 172.

Origines Parochiales Socotiae (1855) the antiquities ecclesiastical and territorial of the parishes of Scotland, 2nd series, Vol. 2, Edinburgh, 611 & 754.

RCAHMS (1911) Third report and inventory of monuments and constructions in the county of Caithness, London, No. 499, 124.

Ritchie, P. R. (1970) 'Thurso, Scrabster, Bishop's Castle', Discovery Excav Scotland, 60.

Smythe (1870) Life of Robert Dick.

Talbot, E. (1970) 'Bishop's Castle, Scrabster, Caithness-An Interim Excavation Report', 11-12-1970.

Talbot, E. (1973) 'Excavations at Bishop's Castle, Scrabster', Caithness Field Club Bulletin, 1st series, Vol. 2, Oct 1973, 7-8.

Talbot, E. (1973) 'A Report of Excavations at Bishop's Castle, Scrabster (ND/106691), 12-09-73.

Talbot, E. (1973) 'Scrabster, Bishop's Castle', Discovery Excav Scotland, 21-22.

Webster, L. E. and Cherry, J. (1974) 'Medieval Britain in 1973', Medieval Archaeol, Vol. 18, 198.

About Scheduled Monuments

Historic Environment Scotland is responsible for designating sites and places at the national level. These designations are Scheduled monuments, Listed buildings, Inventory of gardens and designed landscapes and Inventory of historic battlefields.

We make recommendations to the Scottish Government about historic marine protected areas, and the Scottish Ministers decide whether to designate.

Scheduling is the process that identifies, designates and provides statutory protection for monuments and archaeological sites of national importance as set out in the Ancient Monuments and Archaeological Areas Act 1979.

We schedule sites and monuments that are found to be of national importance using the selection guidance published in Designation Policy and Selection Guidance (2019)

Scheduled monument records provide an indication of the national importance of the scheduled monument which has been identified by the description and map. The description and map (see ‘legal documents’ above) showing the scheduled area is the designation of the monument under the Ancient Monuments and Archaeological Areas Act 1979. The statement of national importance and additional information provided are supplementary and provided for general information purposes only. Historic Environment Scotland accepts no liability for any loss or damages arising from reliance on any inaccuracies within the statement of national importance or additional information. These records are not definitive historical or archaeological accounts or a complete description of the monument(s).

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