Coastal archaeological sites dating to the late Pleistocene and early Holocene are rare on the northwest coast of North America, as they are in many regions of the world, due to changing environmental factors, in particular glacial isostasy and eustasy, resulting in low visibility and survival of archaeological deposits. This dissertation outlines methods and results used to locate late Pleistocene and early Holocene archaeological sites on the Dundas Island Archipelago on the Northwest Coast culture area of British Columbia, Coast Tsimshian Territory, where archaeological sites older than 5,000 years BP are not known. Part of the reason for this is that masses of glacial ice accumulated on the Cordilleran Mountains of North America during the last glacial maximum, which depressed mainland coastal regions isostatically in relation to sea levels. As a result of lateral displacement of subcrustal material, areas to the west of the Cordillera bulged and landforms were raised relative to the sea. With deglaciation, the depressed crust began to rebound and the forebulge subsided resulting in rapidly dropping sea levels along the mainland to the east and rapidly rising sea levels along outer coastal islands to the west. These processes occurred in concert with sea levels that began rising eustatically following the last glacial maximum. Between the inner and outer coasts lies the Dundas Island Archipelago. This research project hypothesized that the study area was close to a sea level hinge lying between these two regions with very different sea level histories. With less significant shoreline movement, it was further anticipated that shoreline situated archaeological sites dating to the late Pleistocene and early Holocene might be found in close proximity, although slightly higher than the present day shoreline. This dissertation addresses the following question: Where are late Pleistocene and early Holocene archaeological sites situated on the Dundas Island Archipelago? To address this question, this dissertation details the methods and results used to determine a sea-level and vegetation history for the Dundas Island Archipelago and the archaeological prospection that was undertaken along relict shorelines. Pollen analysis of sediments from a lake core identified a sequence of six vegetation zones beginning before 12,385 BP. Based on diatom identification of cores from four lake basins, combined with supporting indicators, a sea level curve for the Dundas Islands was constructed showing a slow regression of shorelines from 13 m above the barnacle line to present day elevations over the last 12,000 years BP. Drawing upon these palaeo-environmental data, areas were selected for archaeological survey and prospection. Field testing of these selected areas resulted in the identification of five archaeological sites dating to the early Holocene. These are the first archaeological sites dating older than 5,000 years BP that have been found and dated in Coast Tsimshian Territory. The elevations and radiocarbon dates on all archaeological deposits are consistent with the sea level curve based on palaeo-environmental data points. Overall, this dissertation draws upon palaeo-environmental methods and results for the purpose of identifying and interpreting archaeological sites situated on raised marine landforms.