MHG1360 - Cairn Merk Broch


Remains of Iron Age broch.

Type and Period (1)

  • BROCH (Iron Age - 550 BC to 560 AD)

Protected Status

Full Description

'Broch', Carn na Mairg. Subcircular grass-covered mound, the outer wall exposed on E flank. Above it a section of mural gallery 2 x 0.9 x 0.6m is evident. It is surrounded by a ditch crossed by three causeways, two of which are modern.
[On opposite river bank from ND15SW 22]: Structure (ND 1321 5102). Dimensions: 6 x 5.2m. Rectangular structure in ruinous condition. ['Remains of fosse'is marked at this location on first edition of OS 6-inch map (Caithness 1876, sheet xxii), but nothing is marked on current edition of OS 1:10,560 map (1963) except for a nearby modern drain. - Infor from RCAHMS (FO) 21 August 1996]
R J Mercer, NMRS MS/828/19, 1995

Cairn Merk or Carn na Mairg: a broch generally as described. The 'chamber' noted in previous field report is a section of mural gallery. The two later causeways are of neatly coursed slabs and upstanding whereas original causeway is low and turf-covered, only line of W edge being clear. The walls flanking the approach from the causeway to the broch entrance are checked 3.5m distant from broch. There is no evidence of a flanked approach beyond causeway; the mound or mounds mentioned are natural or in part spoil.
Visited by OS (J M) 11 November 1981.

(ND 1331 5103) Cairn Merk (NR) OS 6" map, (1963)

A broch known as 'Carn na Mairg' is situated on E bank of River Thurso about half a mile S of Westerdale. It is a conspicuous, grass-covered mound rising from water's edge and cut off from the moorland by a well-defined ditch opening on the river bank, wet in bottom and filling when river is in flood. This ditch measures some 22ft in width on the SE and about 15ft on the NE. From the top of the parapet which crowns the scarp it is from 8 to 10ft deep, but its depth from the top of the outer bank is only 2 to 3ft. Towards the E the continuity of the ditch is broken by the approach to the broch which crosses on the solid and is 6ft wide where it passes through the enceinte. On either side of this approach as it crosses the ditch, the foundations of a wall are visible beneath the turf, and beyond it on the moorland two parallel mounds or ruined walls exist for a distance of some 50ft, 24ft a part and measuring 17ft across at base, indicating direction of road, inclining obliquely towards entrance. Between ends of these flanking mounds and ditch, an old road now interposes. The parapet wall on the top of the scarp has been some 4 to 5ft in thickness, and has been carried entirely round the broch. Between it and the base of the tower has been a level space some 30ft in width over which numerous flagstones set on end protrude from the turf. The outer end of entrance passage of broch has been exposed to a height of 2ft 3ins, as also inner end, while in one or two places on exterior small portions of wall are visible. The entrance has been from E through a passage 10ft 6ins in length, 3ft 4ins wide at the exterior, and 2ft 4ins wide at interior extremity. The outer lintel has gone, but succeeding four remain in situ, roofing passage for 8ft of its length. No guard chamber or door jambs are exposed. The overall diameter is about 52ft. The greatest height of mound is 8ft above level of passage floor. A depression in top marks the court.
Visited by OS (E G C) 11 April 1962.

The remains of broch are generally as described by RCAHMS. Attempts at excavating have taken place on E side, and here outer wall of the broch is exposed for 3.5m and height of 2.4m. Above the wall and to the W, a chamber is exposed; it is 2m by 0.9m and 0.6m deep at present. NE of wall another short section of wall is now visible, probably part of parapet wall which extended round top of scarp of ditch; this wall is 1.1m high.
There are two modern causeways over ditch on NE side, both similar to entrance causeway, but varying in width, being 1.7 and 1.5m wide respectively. On SE side of ditch and in line with entrance to broch are remains of entrance causway, now 0.3m high above base of ditch.
Only one of flanking mounds indicating approach road is now evident, second mound no doubt having been destroyed when new road which now skirts site was constructed.
The broch's surrounding ditch has been largely destroyed on SE and S sides by modern drainage.
Resurveyed at 1:2500. Visited by OS (E G C) 11 April 1962.

Cairn Mairg' (Brough) (NR) Fosse (NR)
OS 6" map, Caithness, 2nd ed., (1908)

This site was included in Mackie's 2007 'The Roundhouses, Brochs and Wheelhouses of Atlantic Scotland c.700 BC - AD 500: Architecture and material culture'. See link below to HES Canmore record which includes the chapter on this site. <1>

The broch was subject to topographic and photogrammetric surveys by Headland Archaeology in 2018 as part of archaeological condition on the Achlachan Wind Farm development. The surveyed profile indicates that the walls survive to a height of some 4m above the original ground surface. <2>

Sources/Archives (6)



Grid reference Centred ND 1331 5103 (70m by 70m) (2 map features)
Map sheet ND15SW
Civil Parish HALKIRK
Geographical Area CAITHNESS

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