Achensee, Lake, Tyrol, alt. 929 m, area 6.8 km2%sup ,/% 9 km long, 1 km wide, up to 133 m deep. Tyrol's largest lake, formed by moraines of the Inn Glacier; north of Jenbach, between the Karwendel mountains to the south and west and the Rofan Mountains to the east. Lake Achensee originally fed the stream to the River Isar. Since 1927 Lake Achensee has been a reservoir for the Achensee-Wasserkraftwerk (Hydroelectric Power Plant) in Jenbach; which is powered by the 380 m drop from Achensee to the Inn Valley. Archduke Ferdinand II (1529-95) had Venetian ships brought to Lake Achensee for the court. Once tourism had begun to develop, the first steamship was launched on the Lake in 1887; in 1889 the first steam-powered cog railway in Europe was built between Jenbach and Seespitz (7 km). Shipping service. Lakeside towns include Seespitz, Pertisau, Scholastika, Seehof, and Buchau.
Further reading#F. Wachter, Der Achensee, 1933; Kraftwerk Achensee, 1956.