Mielno [ˈmjɛlnɔ] is a village in the administrative district of Gmina Grunwald, within Ostróda County, Warmian-Masurian Voivodeship, in northern Poland. It lies approximately 26 kilometres (16 mi) south-east of Ostróda and 37 km (23 mi) south-west of the regional capital Olsztyn.