Aargau

Aargau, formally the Canton of Aargau, is one of the 26 cantons that make up the Swiss Confederation. It lies in the north of the country, and its name means the Aare province, after the Aare River whose lower course runs through its territory. The canton is divided into eleven districts and its capital is the city of Aarau. It is one of the most densely populated parts of Switzerland, with an official estimate of about 743,600 residents at the end of 2025 over roughly 1,400 square kilometres. The present canton took shape in 1803 under the Act of Mediation, when three short-lived cantons of the Helvetic Republic, Aargau, Baden and Fricktal, were combined into one.