Färnebofjärden National Park (Swedish: Färnebofjärdens nationalpark) is a Swedish national park traversed by the river Dalälven, about 140 km (87 mi) north of Stockholm. It covers 10,100 ha (25,000 acres), of which 4,110 ha (10,200 acres) aquatic, on the frontier between the counties of Dalarna and Gävleborg.
After the retreat of the ice sheet that covered the region after the last ice age, the river found itself rerouted by an esker onto a plain uniquely ribbed by the ridges of other eskers, where it formed a succession of rapids and wide bays (called fjärdar), which the river inundates during the spring floods. This particular hydrography, along with the park's proximity to the ecological frontier between the north and the south, has favored the development of a fauna and flora of great biodiversity.