Bottom sediments from Lake Pervoe Starushechye, on the White Sea shore, near Korabelnaya Bay, Chupa Town, 500 m from an archaeological site, were analyzed. The aim of our studies was to determine the position of the sea shoreline, to correlate archaeological sites relative to it, to date ancient settlements, and to reconstruct the paleoclimatic conditions and habitats of ancient people. Spore and pollen, diatom, and radiocarbon (14C) analyses were done. New evidence for the time of retreat of the seashore, the isolation of Lake Pervoe Starushechye from it and the time of the possible invasion of the area by ancient people was obtained. People were shown to inhabit the area from 3970 ± 120 to 3250 ± 120 14С y.a., when the sea shoreline reached modern levels of 19–22 m. The lake was then a ~8 m deep White Sea bay, in which marine gyttja was deposited. These events are reflected in the stratigraphy of the sequence and supported by the results of diatom and spore and pollen analyses. About 3500 y.a., mean annual temperatures in North Karelia were 2°С and annual precipitation ~50 mm/year higher than modern values. Spruce and pine-spruce forests with aspen and alder patches grew on the shore. A favorable climate and exuberant vegetation attracted people. Therefore, it is at the Atlantic-Subboreal boundary that the archaeological sites located at the above altitudes could arise. The lake separated from the White Sea 3020 ± 90 14С y.a. Freshwater sapropel was deposited in the isolated lake, as indicated by the composition of diatom flora and spore and pollen spectra. The sea shoreline declined to 17–16 m. Light-coniferous pine lichen-green moss forests with light-loving oligotrophic grasses were spreading actively throughout the study area.