Due to its proximity to Bergen, Os experienced strong population growth.

Other large villages in Os included Hagavik, Halhjem, Søfteland, Søre Øyane, and Søvik.

[5] The parish of Os was established as a formannskapsdistrikt, the predecessor of today's municipalities, on 1 January 1838.

[6] During World War II, the Ulven concentration camp was used by the occupying Nazi German Army.

The charge has a tincture of Or which means it is commonly colored yellow, but if it is made out of metal, then gold is used.

The rowboat design was chosen to symbolize the Oselvar boat which is commonly built and used in this area.

The roses in the coat of arms stand for the art of rosemåling which has long been used for decorations in the area.

The small roses in the design corresponded to the number of school districts in Os when the coat of arms was new.

[12] The municipal council (Kommunestyre) of Os was made up of 35 representatives that were elected to four year terms.

The village area of Søre Øyane was located on several small islands off the mainland shore.

This small wooden boat was named after its major important building site during the 18th century, at the mouth of the Oselva River.

They still build these boats the traditional way in Os, and tourists are able to visit and watch them work.

The European route E39 highway passed through Os from the city of Bergen (to the north) to the ferry quay at Halhjem, on the shore of the Bjørnafjorden.

There is a ferry from Halhjem to Våge on the island of Tysnesøya in Tysnes municipality, to the southeast.

The Norwegian government is planning to build a bridge or tunnel crossing to provide road access across the Bjørnafjorden as part of the Hordfast project.

[37] In the period from 29 October to 4 November 2001, 45.7% of the workforce of Os commuted out of the municipality, mainly to the neighboring city of Bergen.