Largest fjord in Svalbard with a length of over 100 km. If the Isfjord was completely frozen in winter at the beginning of the 20th century, this only happens now in particularly cold years. Very varied landscape, landscape with geological and climatic diversity. Wide coastal plains in the west, behind which a glaciated alpine mountain world rises with pointed peaks and ridges. Further to the east, the picture changes into a plateau with extensive plateaus at an altitude of 400 to 700 meters, which rise from the other mountains to over 1000 m.

In the Isfjord there are a number of nature reserves that have become bird sanctuaries and whose access is checked seasonally (15 May to 15 August).
The flora for Svalbard is very rich, there are large areas of tundra, especially in the coastal plains and in the large, ice-free valleys. For example, Colesdalen and Reindalen are each one of the most biologically productive and diverse tundras in Svalbard, with great biodiversity and extensive coverage that quickly results in knee-high vegetation and large populations of reindeer and polarfox.