Waldshut-Tiengen, commonly known as Waldshut, is a city in southwestern Baden-Württemberg right at the Swiss border. It is the district seat and at the same time the biggest city in Waldshut district and a "middle centre" in the area of the "high centre" Lörrach/Weil am Rhein to whose middle area most towns and communities in Waldshut district belong. There are furthermore complexities arising from cross-border traffic between this area and the Swiss cantons of Aargau, Schaffhausen and Zürich. This classification relates to Walter Christaller's Central Place Theory, however, and not to any official administrative scheme.

Aargau, 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.