Lake Ilmenak (Belarusian: Возера Ільменак) is a lake in the Braslau Lakes National Park of northern Belarus. It lies about 10 kilometres (6.2 mi) northeast of Braslau.

The lake is small and covers an area of 0.2 square kilometres (0.077 sq mi) with a length of 0.64 kilometres (0.40 mi). The maximum width is 0.47 kilometres (0.29 mi) and the coastline is 1.9 kilometres (1.2 mi). The water volume is 0.61 mln m³ and the catchment area is 2.5 square kilometres (0.97 sq mi). The greatest depth is 6.2 metres (20 ft). The slopes of the valley reach a height of 10–20 metres (33–66 ft), and are wooded in the south, west and north. The banks are low and sandy. Two streams flow into the lake.

• Блакітная кніга Беларусі. — Мн.: БелЭн, 1994.