Clearly, the landscape during the fourth and early third millennia would have looked very different from today, with considerably more tree cover and without the extensive deposits of peat that exist nowadays, although there would have been some blanket peat in some areas during the Neolithic.
Notwithstanding the challenges involved in locating settlement evidence in this peat-covered and mostly un-ploughed modern landscape, the available evidence from all sources strongly suggests a pattern of Neolithic occupation based on coastal areas (eg the Moray and Cromarty Firths), river valleys (eg Strathnaver, Helmsdale, Strath of Kildonan) and lochs (eg Yarrows, Calder, see Mercer 1992). As with elsewhere, the early farmers would have sought out the best available land for cultivating crops and for grazing (of cattle, sheep and probably pigs), and this corresponds to the areas noted above. Occupation of inland areas, usually the upper reaches of river valleys or areas accessible from them, is attested not only by the pattern of funerary monuments (Map 5.5: Chambered cairns) but also, at Lairg, by palynological evidence recently reworked by McDonald (et al 2021), by buried soil beneath Clearance Cairn 1, and by radiocarbon-dated charcoal that may well relate to human activity (McCullagh and Tipping 1998, 203). It may be that the handful of featureless and abraded sherds found in pits beneath Bronze Age Roundhouse 1 at Lairg are of Neolithic date (ibid). No sub-peat field walls, such as have been found in the Outer Hebrides, have been noted in the Highland Region, but some ard-marks from Lairg, along with evidence for intense soil erosion suggestive of cultivation, may relate to agricultural activity that took place as early as 3600–3200 BC. There is also pollen evidence suggesting the cultivation of wheat and barley (and potentially oats), possibly as early as the beginning of the fourth millennium, and certainly during the Later Neolithic (ibid, 203–4; Section 5.4.1).