Lago della Sella, reservoir near St. Gotthard Pass in Airolo, Ticino, Switzerland

Lago della Sella is a reservoir situated above 2200 meters in the Airolo region of Ticino. The water is held by a dam approximately 36 meters tall and stretches about 1.3 kilometers long, surrounded by rocky mountain peaks including Monte Prosa and Pizzo Centrale.

The gravity dam was planned by the Swiss engineer Fritz Gigax and built between 1945 and 1947, with completion in 1947. It is 36 metres high with a crest length of 334 metres and holds 9.2 million cubic metres. Its water is used together with that of the Lucendro reservoir in the Airolo power plant, now operated by Alpiq.

The reservoir lies below the Gotthard Pass road, about 2.5 km by small mountain road from the Ospizio. Its water is used together with that of the Lucendro reservoir in the Airolo power plant, which is now run by the energy company Alpiq.

From the Gotthard Pass hospice a small mountain road runs about 2.5 km to the dam wall. The dam is a gravity structure 36 m high with a 334 m crest, holding 9.2 million cubic metres of water.

The water level fluctuates depending on power generation needs, causing the lake's appearance to change seasonally. These shifts reveal how the reservoir actively functions as part of the region's energy network rather than serving as a static landscape feature.