Mikołajki is a resort town in Mrągowo County, Warmian-Masurian Voivodeship in north-eastern Poland, with 3,852 inhabitants as of 20…Mikołajki is a resort town in Mrągowo County, Warmian-Masurian Voivodeship in north-eastern Poland, with 3,852 inhabitants as of 2017. The town is located near the Śniardwy, the largest lake of both the Masurian Lake District and Poland. It is located in the center of the ethnocultural region of Masuria.