Joachimsthal is a small town in the district of Barnim, in Brandenburg, Germany. It is situated within the Schorfheide-Chorin Biosphere Reserve on the isthmus between the lakes Grimnitzsee in the north and Werbellinsee in the south, about northwest of the district's capital Eberswalde and northeast of the Berlin city centre. The municipality is the administrative seat of the Amt ("municipal federation") Joachimsthal (Schorfheide).