Bergenhus len was a Norwegian administrative division. The "len" was administered from Bergenhus Fortress in Bergen.
Formerly the term len (plural len) in Norway signified an administrative region roughly equivalent to today's counties. The historic len was an important administrative entity during the period of Dano-Norwegian unification. At the beginning of the 16th century the political divisions were variable, but consistently included four main len and approximately 30 smaller sub-regions with varying connections to a main len. Up to 1660 the four principal len were headquartered at the major fortresses Bohus Fortress, Akershus Fortress, Bergenhus Fortress and the fortified city of Trondheim[1]. The sub-regions corresponded to the church districts for the Lutheran church in Norway.
In 1536 Bergenhus was one of four len in Norway and included Northern Norway. These four principal len were in the 1530s divided into approximately 30 smaller regions. From that point forward through the beginning of the 17th century the number of subsidiary len was reduced, while the composition of the principal len became more stable.
From 1660 Bergenhus was one of Norway's nine principal len comprising 17 subsidiary len. With the royal decree of February 19, 1662, each len was designated an amt (plural amt) and the lenmann was titled amtmann, from German Amt (office), reflecting the bias of the Danish court of that period. After 1671 Norway was divided into four principal amt or stiftsamt and there were nine subordinate amt. Bergenhus amt was the stiftsamt and the subordinate amt were Halsnøy klostergods, Hardanger amt, Nordlandene amt.
From 1730 Bergenhus was divided into the following amt:
From 1919 each amt was renamed a fylke (plural fylke) (county) and the amtmann was now titled fylkesmann (county governor).