The Aare or Aar is a tributary of the High Rhine and the longest river that both rises and ends entirely within Switzerland.

The High Rhine is the name used for the part of the Rhine that flows westbound from Lake Constance to Basel. The High Rhine begins at the outflow of the Rhine from the Untersee in Stein am Rhein and turns into the Upper Rhine in Basel. In contrast to the Alpine Rhine and Upper Rhine, the High Rhine flows mostly to the west.