During the 1960s, there were many municipal mergers across Norway due to the work of the Schei Committee.

The name of the river may come from the word toll (Old Norse: þǫll which means "young pine tree".

The mayor was indirectly elected by a vote of the municipal council.

[8] The municipal council (Kommunestyre) of Tolga-Os was made up of 25 representatives that were elected to four year terms.

The party breakdown of the final municipal council was as follows: The mayors of Tolga-Os: