The official blazon is "Azure, a net argent" (Norwegian: Blått dekket med sølv fiskegarn).

This means the arms have a blue field (background) and the charge is part of a fishing net.

The fishing net has a tincture of argent which means it is commonly colored white, but if it is made out of metal, then silver is used.

Several different arms were designed, all with fisheries as the main theme, but the council finally chose this one, which is unique among Norwegian civic heraldry.

Osen was used as a satellite prison camp during the World War Two, mainly for Yugoslavian population.

The Norwegian Meteorological Institute has a weather station located near the Buholmråsa lighthouse, with recording since 1965, showing a marine west coast climate/oceanic climate (Cfb).

The municipal council (Kommunestyre) of Osen is made up of 15 representatives that are elected to four year terms.

The tables below show the current and historical composition of the council by political party.