Mierzwin Duży [ˈmjɛʐvin ˈduʐɨ] is a village in the administrative district of Gmina Wyszki, within Bielsk County, Podlaskie Voivodeship, in north-eastern Poland. It lies approximately 7 kilometres (4 mi) south-west of Wyszki, 19 km (12 mi) west of Bielsk Podlaski, and 39 km (24 mi) south-west of the regional capital Białystok.