Barentsøya has an approximately square shape, with maximum lengths and widths of about fifty kilometers, and an area of . A significant part of the island, more than , is glaciated. The ice cap of Barentsjøkulen covers a large part of the island, with the largest offspring Besselsbreen (north), Duckwitzbreen (west), Freemanbreen (south), and Hübnerbreen (southeast). Barentsjøkulen has the two large ice domes of Peer Gyntslottet and Solveigdomen. The mountain of Schweinfurthberget is a nunatak of Barentsjøkulen.