The valley around Gosau was settled in the 13th century by monks from St. Peter's Abbey in Salzburg. Timber production for the salt mine in Hallstatt was a major industry. In 1490 the town became part of the Principality above the Enns River. The area was repeatedly occupied by the French during the Napoleonic wars. When the Republic of Austria was formed in 1918, Gosau became part of the federal state of Upper Austria. In 1938 the area was annexed by the German Reich along with the rest of Austria, and Gosau became part of the "Gau Oberdonau," only to be returned to Upper Austria when the Republic of Austria was reconstituted in 1945
