On the basis of a systems analysis of the end moraines and indicators of ice flow, the authors contend that the northern margins of Eurasia, including the arctic continental shelves, were entirely and repeatedly glaciated by vast marine ice sheets during the Pleistocene ice ages. All available information on late Pleistocene ice‐marginal features was included in a numerical reconstruction of a three‐dimensional model of the Eurasian Ice Sheet. This reconstruction suggested that the ice sheet was formed by the merging of three major ice domes (the Scandinavian, Kara, and East Siberian domes) and one lesser one (the Chukchi dome). These domes covered respectively 3.4, 6.1, 2.3, and 0.4 million km2, and the total areal extent of the ice sheet was 12.2 million km2. A further 2 million km2was covered by mountain glacier complexes, and no less than 3 million km2was inundated beneath proglacial lakes. According to different determinations, the volume of the last Eurasian Ice Sheet was about 15 to 18 million km3, while an additional mass of ice was incorporated in a floating ice shelf covering the Arctic Basin, 1 to 1.5 km thick. These facts are critical for understanding the geomorphology, sedimentology, hydrochemistry, and physics of the Arctic Ocean. Glacial scouring and glaciomarine deposition may account for the structure of the arctic continental shelf and slope and for the huge accumulations of sediment on the sea bed. Some other features of the ocean seem to have resulted from the impact of the floating ice shelf. This should all be taken into account by future arctic research expeditions.