As with so many Iron Age site types, the definition of a ‘crannog’ has seen much discussion. Much of the attention is focussed on how significant the artificial/partially artificial construction criteria is, and whether natural islands with buildings (‘island duns’) should be included in the crannog definition (Henderson 2002; Cavers 2010; Stratigos forthcoming with refs). There appears to be more of an acceptance of discussing crannogs and the islets on which structures were built together, though the term ‘crannog’ generally persists in meaning a structure that has an element of artificial construction.
Even considering a broad definition of a crannog as an island dwelling, natural or otherwise, for the Highlands the evidence for Iron Age occupation is actually almost entirely comprised of sites that are fully or partially an artificial construction. This is striking because there are numerous possible natural islands in the many lochs throughout the region that would have worked as ‘crannogs’; many of these islets no longer survive but are visible on old maps (Stratigos 2016; 2018). In other words, people could have taken an easier construction option, but seem to have chosen not to. More survey of possible natural island sites however would be useful to indicate if they were used in other periods of prehistory.
Although Neolithic crannogs are now known widely in Eilean Siar (Garrow and Sturt 2019) and a Late Bronze Age origin for crannogs has been postulated (ScARF Iron Age section 5.3), the earliest dates so far in the Highlands for crannogs come from the Iron Age and later (Table 7.4). The tradition is enduring in the Highlands, with the reuse of crannogs common in later periods and some even being built in the medieval period, for example at Loch Vaa, Badenoch and Strathspey (MHG4691) and the post-medieval period, such as Eilean Tigh Na Slige in Loch Treig, Lochaber (MHG4296). Dating of individual sites is therefore crucial before they can be usefully incorporated into local and regional periods and contexts.
The distribution of crannogs known in the Highlands can be seen on map Map 7.2; and further details are available on Datasheet 7.2.
|Loch Migdale||S||796–516 BC;|
41 BC–AD 125
|Two trial trenches for Time Team in 2003. Evidence of causeway||MHG10059; Wessex Archaeology 2003|
|Redcastle||R&C||Nine dates, mainly Early Iron Age||Marine crannog. Tidal link to shore. Structural timbers, showing two phases, including wattle-sided pits. Animal bones and hides suggesting industrial activities. No domestic finds||MHG9112; Hale 2000|
|Carn Dubh, Beauly Firth||I||805–490 BC||GU-4540||Marine crannog. Piles of oak and pine.||MHG3811; Hale 2000|
|Phopachy, Beauly Firth||I||200 BC–AD 90;|
199 BC–AD 54; 100 BC–AD 220; 110 BC–AD 120
|Marine crannog. Separated from shore by tidal channel. Structural timbers||MHG18664; Hale 2000|
|Loch of the Clans I||I||AD 5–130|
20 BC–AD 130
|Excavated 1862; One trench dug in 2010s. Possibly single-phased||MHG6991; Stratigos and Noble 2017|
|Loch Na Claise||NWS||190–38 BC |
113 BC–AD 52
|Precision not known. Partial excavation 2016 found evidence of timber building in circular stone enclosure. Finds of charcoal, burnt bone||MHG12218|
All dates cal at 95.4% probability. For full details of dates, see Datasheet 2.1
Many crannogs of the Highlands were explored between 1908 and 1914 by Odo Blundell, a monk at Fort Augustus Abbey (see Case Study Highland Crannogs and Odo Blundell), and much of the information archaeologists know about crannogs comes from his surveys and excavations. He also reported anecdotal and local knowledge of crannogs; some of the crannogs have not been relocated since his original work (for example MHG7444; MHG2674). In a number of cases the water levels have changed, due to agricultural improvements or hydro schemes (Stratigos 2016; 2018). Since Blundell’s time there has been relatively little research focussed on crannogs in this part of Scotland, compared with major research programmes occurring in Loch Tay, parts of Argyll and southwest Scotland.
The reasons for the occupation of crannogs are still debated. Crannogs are found in areas with other types of settlement (ScARF Iron Age section 5.3). The excavation results from Redcastle in the Beauly Firth are particular interesting, as they seem to show non-domestic use of the crannog, and it is possible marine crannogs, which are not common, had a wider range of functions than those in lochs (Hale 2000). Some Highland crannogs have exceptional preservation and even deep stratigraphy, for example Kinellan, Strathpeffer in Easter Ross (MHG6285) or Loch of the Clans (MHG6991) but early excavations have limited the amount of information which can be obtained about these two sites today.
The potential good preservation at many crannogs holds possibilities for obtaining structural, artefactual and environmental data. The large number of surviving crannogs in the Highlands (Map 7.2) therefore holds great potential for future work. It should also be borne in mind that many more crannogs are likely to be present, fully submerged or in more remote parts of the Highlands, that have simply gone unrecorded. Crannogs in now drained sites are more accessible than mostly or fully submerged sites and thus are more viable targets for survey or excavation, but this comes at a cost. Michael Stratigos noted that the second crannog at Loch of the Clans (MHG6987) has high archaeological and palaeoenvironmental potential due to its likely permanent saturation as compared to the Loch of the Clans I crannog which, 150 years since it was first investigated and following drainage, has lost the greater share of its archaeological and palaeoenvironmental potential (Stratigos and Noble 2017).