[6] The parish of Hitterdal (later spelled Heddal) was established as a municipality on 1 January 1838 (see formannskapsdistrikt law).

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

The old name of the river comes from the genitive case of the word heitr which has an unknown meaning.

On 3 November 1917, a royal resolution changed the spelling of the name of the municipality to Heddal.

[10] The municipal council (Herredsstyre) of Heddal was made up of representatives that were elected to four year terms.