Mierczyn [ˈmjɛrt͡ʂɨn] is a settlement in the administrative district of Gmina Góra Świętej Małgorzaty, within Łęczyca County, Łódź Voivodeship, in central Poland. It lies approximately 7 kilometres (4 mi) east of Łęczyca and 31 km (19 mi) north-west of the regional capital Łódź.