Tarnowo [tarˈnɔvɔ] is a village in the administrative district of Gmina Miastkowo, within Łomża County, Podlaskie Voivodeship, in north-eastern Poland. It lies approximately 8 kilometres (5 mi) south-east of Miastkowo, 15 km (9 mi) south-west of Łomża, and 86 km (53 mi) west of the regional capital Białystok.