The parish of Rendal was established as a municipality on 1 January 1838 (see formannskapsdistrikt law). This municipality was quite large, spanning  from the Østerdalen valley to the border with Sweden.
On January 1, 1838, according to the formannskapsdistrikt law, the parish of Rendal became a municipality. This municipal area was exceptionally expansive, covering the Østerdalen valley up to the Swedish border.