Mikołajki [mikɔˈwai̯ki] (German: Nikolaiken (help·info)) is a town in Mrągowo County in the Warmian-Masurian Voivodeship in north-eastern Poland with 3,849 inhabitants. The village Zełwągi belongs to Mikołajki. The town is located near Śniardwy, the largest lake of the Masurian Lake District.