is a wooded mountain ridge in the municipality of Bærum
. Geologically Kolsås belongs to the Oslo Graben
area. Its two peaks consist of hard rhomb porphyric lava
covering softer rocks, forming steep cliffs to the east, south and west.
Protected landscape area
The area from Kolsås to Dælivannet is a protected landscape area from 1978 (five square kilometers), with four nature reserves: Skotta, Dalbo, Kolsåsstupene and Kolsåstoppen nature reserve.
Kolsås has been a training area for climbers since beginning of the 20th century. Today it is the largest rock climbing area
in the Oslo region. The wall Øvre Sydstup
on the southern wall has more than 200 climbing routes.
The northern hillside of Kolsås has alpine skiing facilities.
is part of the subway rail system Oslo T-bane
, running from downtown Oslo to Kolsås station
, via Gjettum station
and Hauger station
The military base Kolsås leir
, partly located inside the mountain, was home of NATO's Allied Forces Northern Europe
(AFNORTH) until 1994.
The area has occurances of old petroglyphs
and limestone quarries
The French painter Claude Monet painted Mont Kolsaas in 1895.
The last element in the name is ås m 'mountain ridge'. The first element is probably the genitive case of the old male name Kolr. (An old farm lying beneath the mountain has the name Kolsberg, and this farm is probably named after the same person.)