The Outer Hebrides Coastal Community Marine Archaeology Pilot Project (OHCCMAPP) considered a range of themes across the Outer Hebrides including Maritime History and Transport, Marine Resource Exploitation and Submerged Prehistory potential. This paper introduces the past landscape component, introducing palaeogeographic reconstructions for the Sound of Harris for the mid-Holocene as proxy scenarios for Mesolithic seascapes. These scenarios are based on publiclyavailable bathymetric datasets, community-informed field investigations and published sources. The implications for the interpretation of the terrestrial archaeological record are discussed with a focus on maritime connections and distribution of intertidal land and by association coastal resources such as shellfish. Areas of potential are identified for future investigation. The influence of sea-level rise on the coastal configuration is considered for the Mesolithic, in particular the positive impact of increased intertidal zone area and increased penetration into the interior of the landscape by boat. A major seaway is indicated linking the Atlantic to the Minch close to the Harris coast in the early Holocene, which provides a direct context for interpreting the Mesolithic (and later periods) at Northton, Harris within a maritime framework.