The city of Innsbruck bought the lake in 1919 from the St. Georgenberg-Fiecht Abbey, who had received it from the rulers of Schlitters around 1120.
Since 1924, the lake is managed by the Tiroler Wasserkraft AG.
Achen Lake is the largest lake within the federal state and has a maximal depth of 133 meters. Together with the Achen Valley, it parts the Karwendel mountain range in the west from the Brandenberg Alps in the east.
In winter, the level of the lake is lowered by up to 6 meters.
In 1959 the St. Benedikt was replaced with a modern ship of the same name with a diesel engine. In 1971 the Tirol was replaced with a larger Tirol II for 40 passengers. In 1994 the MS Tirol went into service, replacing the Stadt Innsbruck, and in August 2007 the MS Stadt Innsbruck replaced the St. Benedikt.
Lake Achen is a lake north of Jenbach in Tyrol, Austria.
The Achensee is 9 km long and 1,3 km at its widest point
The deepest point of the lake is 133 meters.
Since 1927 the water of the lake has been used for generating electricity.
The water temperature of the lake is rather low and hardly amounts to 20 degrees, only at the southern bank, the lake reaches about 22 degrees.