Axel Heiberg Island, Nunavut, 43 178 km², third-largest in the Arctic QUEEN ELIZABETH ISLANDS and seventh-largest in Canada, is separated from ELLESMERE ISLAND to the east by Eureka and Nansen sounds. Mountains of the Princess Margaret Range rise precipitously on the west, reaching a height of 2210 m. Ice fields and glaciers cover 14 733 km² of the mountains.

The eastern part is hilly, with local plains. It was on this side of the island that large tree stumps were discovered in 1985. The stumps have since been dated at 40 million years old, evidence that the Far North was at that time much warmer and wetter. This "Fossil Forest" is not petrified but contains all its organic matter, making it a unique glimpse into an ancient ecosystem. The stumps, logs, seeds, cones and leaves are in some cases so well preserved that it is difficult to distinguish them from present-day samples. The most common tree species is dawn redwood (Metasequoia sp), but LARCH, plane-tree sycamore (Platanus sp), Chinese water chestnut (Glyptostrobus sp), SPRUCE and PINE have also been found. Animal evidence of semitropical Axel Heiberg was found in the late 1990s when alligator and turtle fossils were found at Mokka Fiord and fossilized tooth fragments of an extinct huge rhinoceroslike herbivore, Brontotheriidae, were found in the fossil forest site.

The climate today is much colder and vegetation is scant, but well-vegetated spots occur in the lowlands. Arctic hares are the most common mammals. Muskoxen occur in the lowlands, but caribou are scarce. The island was discovered in 1899 by a Norwegian expedition led by Otto SVERDRUP, who named it after the Norwegian consul.