Aargau (German: Kanton Aargau [ˈaːrɡaʊ] (listen); sometimes Latinized as Argovia; see also other names), more formally the Canton of Aargau, is one of the 26 cantons forming the Swiss Confederation. It is composed of eleven districts and its capital is Aarau.
Aargau is one of the most northerly cantons of Switzerland. It is situated by the lower course of the Aare River, which is why the canton is called Aar-gau (meaning "Aare province"). It is one of the most densely populated regions of Switzerland.