Mielno is a village in the administrative district of Gmina Mieleszyn, within Gniezno County, Greater Poland Voivodeship, in west-central Poland. It lies approximately 8 km east of Mieleszyn, 15 km north of Gniezno, and 56 km north-east of the regional capital Poznań. During the German occupation (World War II), in 1939, the Germans carried out massacres of Poles in Mielno, the first already on September 9, 1939, in the second week of the invasion of Poland (see Nazi crimes against the Polish nation).