Kosiły [kɔˈɕiwɨ] is a village in the administrative district of Gmina Rajgród, within Grajewo County, Podlaskie Voivodeship, in north-eastern Poland. It lies approximately 5 kilometres (3 mi) west of Rajgród, 15 km (9 mi) north-east of Grajewo, and 76 km (47 mi) north-west of the regional capital Białystok.