Hallingdal is one of the major valleys of eastern Norway, on an area of 5,830 square kilometers. Hallingdal lies in the northern part of the county of Buskerud. The valley stretches from Gulsvik by Lake Krøderen to the border with Hordaland and Sogn og Fjordane. Central to the geography is relatively flat mountain area which lies from 700 to 1100 meters above sea level. The valley is V-shaped and is drained by the Hallingdal River which originates in the western parts of Hardangervidda and flows eastwards later southwards through Hallingdal.