Aar

The Aar, also spelled Aare in German and sometimes rendered Aar in English texts, is a river in Switzerland. With a length of about 295 kilometers, it is the longest river that runs entirely within Swiss borders. Its source lies in the Bernese Alps at the Grimsel Pass, and it flows northward across the Swiss plateau.

The river leaves Lake Brienz and then continues north, passing through the city of Bern and moving onward past Aarau and Brugg before joining the Rhine at the town of Koblenz in the canton of Aargau. Along its course, the Aar drains a large portion of central Switzerland and collects water from numerous tributaries, supporting hydroelectric power generation and shaping local ecosystems and urban development. The Aare valley is home to many towns and recreational areas; in Bern the river bisects the old town and is a popular site for swimming and riverside promenades during the summer.

Name and significance: The name Aare/Aar is of pre-Roman origin and is a central feature in Swiss geography and history. The river has played a key role in the development of settlements along its banks and remains an important element of Swiss hydrology, ecology, and tourism. The Aar is also used in various contexts to refer to the river in different languages and regional references, but it is most commonly associated with the Swiss watercourse.