Derc is a village in the administrative district of Gmina Jeziorany, within Olsztyn County, Warmian-Masurian Voivodeship, in northern Poland. It lies approximately west of Jeziorany and north-east of the regional capital Olsztyn.
While traditionally Prussian, with the Second Peace of Thorn in 1466 the area became part of the Kingdom of Poland until 1772; 1772-1945 Kingdom of Prussia and Germany ( East Prussia). Following World War II the native German populace was expelled and replaced by Poles.
The village has a population of 660.