Aluksne lake is the eleventh biggest lake in Latvia. The lake is situated 183.7 m above the sea level. There are four islands - Cepurīte (Little Hat Island), Garā (Long Island), Tīklu (Net Island), and Pilssala (Castle Island), and the Cemetery Peninsula. They all are significant in the history and culture of the town. The lake is a favorite place for fishing and relaxation all year round. The most common fish are pikes, breams, sanders, tenches, perches, roaches, European ciscos, eels, and whitefish. It is told that the European ciscos were taken from Aluksne castle to the courts of Petersburg and Berlin.