Pollen, plant macrofossil and charcoal analyses are presented from two of the Aukhorn group of peat mounds which are located in an extensive area of blanket peat on the Caithness Plain north-west of Wick. Radiocarbon dates have been obtained for selected horizons in one of the mounds. The vegetational and fire history are outlined for this area of the Caithness Plain over the past 8000 years. Evidence for fire is present in the earliest deposits and there are signs of human interference with the sparse woodland cover from 5000 bp onwards. Events associated with the initiation of the blanket peat are described and the possible processes involved are discussed. There is evidence that peat initiation was accompanied by widespread burning and in the earliest example by a change in vegetation from open grassland through Calluna heath to wet birch woodland. The possible involvement of Mesolithic populations in this transition is discussed. Localized mounding of the peat began c. 5000 years bp. It apparently resulted from a coincidence of local mire stratigraphy or subpeat soil conditions such that water was retained and local peat accumulation rate maintained above that of the surrounding mire surface at a time of increased desiccation. Surface fires are considered to have acted to amplify the effect. © New Phytologist. Abstract reproduced by permission.