De Weerribben-Wieden National Park is a national park in the Steenwijkerland municipality of the province of Overijssel, Netherlands. Comprising the largest bog of northwestern Europe, the park consists of two areas, De Weerribben and De Wieden, and has an area of roughly 100 square kilometres (39 sq mi). The park was founded in 1882, but De Wieden was added only in 2009