The plateau is the largest peneplain in Europe, covering an area of about at an average elevation of. The highest point on the plateau is the Sandfloegga, which reaches a height of. The landscape of the Hardangervidda is characterised by barren, treeless moorland interrupted by numerous pools, lakes, rivers and streams. There are significant differences between the west side, which is dominated by rocky terrain and expanses of bare rock, and the east side, which is much flatter and more heavily vegetated. The climate also varies between the two sides: it is considerably wetter on the west side than on the east, with over per year recorded in some parts. The prominent peak of Hårteigen is visible across much of the plateau. Much of the Hardangervidda's geology is extremely ancient. The rolling fells of the Hardangervidda are the remnants of mountains that were worn down by the action of glaciers during the ice ages. The bedrock is mainly of Precambrian and Cambro-Silurian origin. The area of Hardangervidda was once part of the Sub-Cambrian peneplain before it was thrusted-over by the nappes of the Caledonian orogeny in Paleozoic times. Much later, in the Miocene epoch, the modern flatness of Hardangervidda took form as a peneplain formed at sea level. Then in Early Pliocene times Hardangervidda and the whole of southern Scandinavian Mountains were uplifted more than thousand meters. , a characteristic mountain on Hardangervidda on a rock of the Hardangervidda
Flora and fauna
The whole of the Hardangervidda is above the tree line. Its alpine climate enables the presence of many species of arctic animals and plants further south than anywhere else in Europe. Its wild reindeer herds are among the largest in the world, with some 15,000 animals recorded in 1996 and about 8,000 in 2008. They migrate across the plateau during the year, moving from their winter grazing lands on the east side of the Hardangervidda, where they graze on lichen, to their breeding grounds in the more fertile west of the plateau. On August 26, 2016, 323 were killed by lightning, prompting a Norwegian Environment Agency discussion on whether to leave so many corpses in the open. The varying climate of the plateau has a marked effect on the flora, which is richer on the wetter west side than in the drier east; much of the plateau is covered by coarse grasses, mosses and lichens. Ciclosporin, an immunosuppressant drug widely used in organ transplantation to prevent rejection was initially isolated from the fungus Tolypocladium inflatum, found in a soil sample obtained in 1969 from Hardangervidda. In the Holocene climatic optimum 9,000–5,000 years ago, the regional climate was warmer, and large parts of Hardangervidda were wooded; pine logs can still be found preserved in bogs well above today's treeline. With the predicted warming, Hardangervidda could again be largely wooded.
The Hardangervidda has been occupied for thousands of years; several hundred nomadic Stone Age settlements have been found in the area, most likely related to the migration of the reindeer. Ancient trails cross the plateau, linking western and eastern Norway. One example is the "Nordmannsslepa" linking Eidfjord and Veggli in the Numedal valley with Hol and Uvdal. It is still a key transit route between Oslo and Bergen. The Bergen Line and the main Norwegian National Road 7 cross the plateau.
Norwegian music projects Ildjarn and Nidhogg combined their talents to produce two ambient albums, one titled 'Hardangervidda Part I' and the other 'Hardangervidda Part II', inspired entirely by this zone. The final two acts of the play When We Dead Awaken by Henrik Ibsen, are set in a mountain health resort in Hardangervidda. Location shooting for the Hoth sequences in The Empire Strikes Back took place on the Hardangerjøkulen glacier. The title theme of the Norwegian film O'Horten, by Norwegian composer Kaada, is titled Across the Hardanger Mountain Plateau and features a train crossing the area.
