Brzezia [ˈbʐɛʑa] is a village in the administrative district of Gmina Sanniki, within Gostynin County, Masovian Voivodeship, in east-central Poland. It lies approximately 5 kilometres (3 mi) south-east of Sanniki, 34 km (21 mi) east of Gostynin, and 74 km (46 mi) west of Warsaw.