Unteraargau

The Unteraargau is the lower watershed of the Aar River in the Swiss canton of Aargau.

It corresponds approximately to the canton's southwestern districts of Aarau, Brugg, Kulm, Lenzburg and Zofingen.

The region was held by the Swabian counts of Lenzburg and Kyburg, in 1264 it fell to the House of Habsburg.

Until 1415, the region belonged to the Further Austrian possessions of Archduke Frederick IV of Habsburg.

His former subjects agreed to acquire the land, and the Bernese citizens of the Swiss Confederacy were the first on the ground.