Mikołajskie Lake covers about 5 square kilometres (1.9 sq mi) and is 5.8 kilometres (3.6 mi) long and 1.6 kilometres (0.99 mi) wide with a maximum depth of 25.9 meters.

In the south-east, Mikołajskie Lake is connected with the Śniardwy Lake by the Przeczka strait within Dybowski Róg and Popielski Róg.

On the west bank extends the Pisz Forest.

On the shore of the lake are the towns: Mikołajki, Dybowo, Kulinowo, Wierzba.

This Mrągowo County location article is a stub.