Sośnia [ˈsɔɕɲa] is a village in the administrative district of Gmina Radziłów, within Grajewo County, Podlaskie Voivodeship, in north-eastern Poland. It lies approximately 15 kilometres (9 mi) north-east of Radziłów, 21 km (13 mi) south-east of Grajewo, and 56 km (35 mi) north-west of the regional capital Białystok.