Königsee is a town and a municipality in the district of Saalfeld-Rudolstadt, in Thuringia, Germany. It is situated 12 km east of Ilmenau, and 35 km south of Erfurt. The present municipality was formed on 31 December 2012 by the merger of the former municipalities Königsee and Rottenbach, under the name Königsee-Rottenbach. On 1 January 2019 the former municipalities Dröbischau and Oberhain were absorbed, and the name was changed to Königsee.