A total of 70 surface samples were collected from Northwestern Canada and Alaska in the American-German Cooperation Expeditions to North America in 2022, 2023 and 2024: 32 surface samples were collected in 2022, 23 samples were collected in 23 and 15 samples were collected in 2024. All originate from moss/soil pollsters. Coordinates of the sampling sites were obtained by hand-held Global Positioning System (GPS). The altitudes of the sampling sites range from 20 to 1704 m above sea level. At least 300 terrestrial pollen and spore grains were counted and identified in each sample under a microscope at 400X using published pollen atlases and identification keys. Pollen percentages were calculated based on the total number of terrestrial pollen grains. Ecoregions, including Boreal Forest/Taiga, Temperate Conifer Forests and Tundra, of each sampling site were extracted from a 1:30 million scale vegetation map for the land area. The fieldwork was planned and carried out by researchers from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI). It took place in the summers of 2022, 2023 and 2024.