Østerdalen is a valley and
traditional district in
Hedmark County, in
Eastern Norway. It consisting of the municipalities
Rendalen,
Alvdal,
Folldal,
Tynset,
Tolga and
Os in the north,
Elverum,
Stor-Elvdal,
Engerdal,
Trysil and
Åmot in the south. It historically included
Särna and
Idre, today in
Sweden.