Postronna [pɔsˈtrɔnna] is a village in the administrative district of Gmina Koprzywnica, within Sandomierz County, Świętokrzyskie Voivodeship, in south-central Poland. It lies approximately 7 kilometres (4 mi) north-west of Koprzywnica, 18 km (11 mi) west of Sandomierz, and 70 km (43 mi) south-east of the regional capital Kielce.