Jaczew [ˈjat͡ʂɛf] is a village in the administrative district of Gmina Korytnica, within Węgrów County, Masovian Voivodeship, in east-central Poland. It lies approximately 6 kilometres (4 mi) north of Korytnica, 15 km (9 mi) north-west of Węgrów, and 64 km (40 mi) north-east of Warsaw.