Offensee

The Offensee is a mountain lake in the Salzkammergut region of Upper Austria, near Ebensee on the Traunsee. It lies at the northern foot of the Totes Gebirge range, 649 metres above sea level. The lake drains into the Offenseebach, which flows via the Traun into the Danube. Its nutrient-poor waters and largely natural shoreline support a wide variety of plants and animals. Since 1965 the area has been protected as a nature reserve. The lake belongs to the Austrian Federal Forests and is a popular spot for swimming and day trips. The lake is roughly 960 metres long and 850 metres wide, covering about 57 hectares. Its average depth is 19 metres, with a maximum of 38 metres in the southern basin. Steep, stony shores line the longer sides, while the northern and southern ends are shallow and bordered by wide reed and grass zones. Two peaks, the Eibeneck and the Gschirreck, rise above the western and eastern shores. A closed forest road circles the lake, accessible only on foot or by bicycle. Visitors find a quiet, forested setting with clear water and few buildings. The southern shore has a small car park and a footpath along the water’s edge. The northern shore features a broad reed bed and a small peat bog where stiff sedge grows. Cold-water stoneworts carpet much of the lake bed, and dense beds of charophytes appear in the shallows. The steep drop-offs along the eastern shore offer sheltered swimming spots in summer. The surrounding hills, part of the Totes Gebirge, rise steeply from the lake, creating a sheltered microclimate with frequent cloud cover and high rainfall.