What is "sihl"

The Sihl is a Swiss river that rises near the Druesberg mountain in the canton of Schwyz, and eventually flows into the Limmat in the centre of the city of Zürich. It has a length of , including the Sihlsee reservoir, through which the river flows. Water is abstracted from the river at the Sihlsee, leading to decreased downstream water flows and a consequent negative impact on water quality.

The river flows through, or along the border of, the cantons of Schwyz, Zürich and Zug. The main settlements of the Sihl Valley are all in the canton of Zürich, and include the towns of Langnau am Albis and Adliswil, along with a south-western segment of the city of Zürich. Above Langnau am Albis, some from the confluence with the Limmat, there are no major settlements alongside the river, and only a few small villages. Whilst the town of Einsiedeln is situated close to the Sihlsee, it is actually in the valley of a tributary river, the Alp.