Knockfarrel Fort

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This image is from the Megalithic Portal, image links to their site reference page.

Knockfarrel is a remarkably intact vitrified fort whose very first trenches helped launch Scottish field archaeology. Beneath the fused rampart and distinctive wing-walls almost everything – date, occupation density, reason for firing – remains conjectural. A light-touch programme of dating and geophysics could transform this iconic ridge-top from a picturesque curiosity into a chronologically-anchored keystone of Highland prehistory.

Knockfarrel / Knock Farril – the vitrified fort of Strathpeffer

Setting & ground plan

Location – Grid ref. NH 5045 5850; the fort crowns the ENE tip of the long Druim Chat ridge above Strathpeffer, 214 m a.s.l., overlooking the Cromarty Firth and the Beauly corridor. (Canmore)

Core enclosure – Lozenge-shaped interior ≈ 118 m × 30 m (0.33 ha) bound by a single timber-laced wall c. 4-5 m thick. The fabric is heavily vitrified all the way round, with glassy basaltic slag up to 0.6 m deep. (hillforts.arch.ox.ac.uk, her.highland.gov.uk)

Wing-walls / outworks – At each end a spine-like wing-wall runs a further 50 m along the ridge crest, visually doubling the length of the fort and creating ‘look-out posts’ highlighted in the scheduling statement. (hillforts.arch.ox.ac.uk, Historic Environment Scotland)

Entrances & trenches – No faces survive, but topography and early sketches suggest the main entrance lay on the gentler south-west approach; three straight cuts visible today are the scars of 18th-century trenches, not prehistoric ditches. (Canmore, her.highland.gov.uk)

Timeline of investigation

Knockfarrel Fort - OS Series 1 - National Library of Scotland	Knockfarrel Fort - OS Series 1 - National Library of Scotland
Knockfarrel Fort - OS 6inch 1915 - National Library of Scotland	Knockfarrel Fort - OS 6inch 1915 - National Library of Scotland

Key physical & scientific observations

Vitrification style – Blocks display vesicular green-black glass and casts of vanished timbers, indicating temperatures > 1100 °C under oxygen-limited firing. (archhighland.org.uk)

Look-out posts – The flanking wing-walls terminate on slight knolls that may have carried watch-huts; this pairing of a compact core with outlying sentry posts is unique among Highland vitrified forts. (Historic Environment Scotland)

Inter-visibility network – Lines of sight link Knockfarrel to Ord Hill and Craig Phadrig across the Moray Firth, suggesting the ridge formed part of an Iron-Age/Pictish signalling chain. (The Modern Antiquarian)

Chronology & cultural horizon

Direct dating is still absent, but comparative morphology and the regional pattern of vitrified forts point to mid-Iron-Age construction (c. 400–200 BC). The strategic siting and later Pictish reuse of similar forts have led some scholars to propose an early-medieval re-occupation phase, though this remains to be tested. (her.highland.gov.uk, ancientworlds.net)

Why Knockfarrel matters

• Type-site for vitrification studies – Williams’ 1770s trenches made the fort a cradle of Scottish archaeological science.
• Exceptional Preservation – Continuous slag outcrops provide stable faces for micro-CT, geochemical or archaeomagnetic sampling.
• Landscape dominance & signalling – The ridge-top design plus twin look-outs offer a textbook case for research into prehistoric communication networks.

This had substantial ramparts made of stones with a timber frame, enclosing a large area and making good use of the natural defences of the hill-top. At some time, the timber of the walls was set on fire, creating enough heat to melt the rock. This vitrification can be seen all around the perimeter of the fort.

Site Gallery

Knockfarrel_5_WS

Knockfarrel_4_WS

Knockfarrel Fort – OS Series 1 – National Library of Scotland

Knockfarrel Fort – OS Series 1 – National Library of Scotland 3

Knockfarrel Fort – OS Series 1 – National Library of Scotland 2

Knockfarrel Fort – OS 6inch 1915 – National Library of Scotland

Knockfarrel Fort – OS 6inch 1915 – National Library of Scotland 3

Knockfarrel Fort – OS 6inch 1915 – National Library of Scotland 2