Dalarna County (Swedish: Dalarnas län) is a county or län in middle Sweden (Svealand). It borders the counties of Uppsala, Jämtland, Gävleborg, Västmanland, Örebro and Värmland. It is also bordered by the Norwegian counties of Hedmark and Trøndelag in the west. Its former name was Kopparberg County (Swedish: Kopparbergs län) until it was changed to the name of the provincial region on 1 January 1997.
The term Dalarna County is mainly used for administrative purposes, being further subdivided into municipalities (kommuner). Dalarna County virtually encompasses the historical province Dalarna (literally, "the valleys"), that deals with history and culture of the area.