The Regenkreis, with Straubing and later Regensburg as its capital, existed between 1806 and 1837 as one of the 15 districts of the Kingdom of Bavaria.

Between 1806 and 1808, the Kingdom of Bavaria was divided into 15 (state) districts named after rivers.

Regenkreis was the predecessor of the Regierungsbezirks Oberpfalz (Administrative Regional District of Upper Palatinate).

The Regenkreis was initially composed of 13 rural divisions and, since 1809, of the independent city of Straubing.

At the request of King Ludwig I, the Territorial Reorganization (Gebietsreform) of 29 November 1837 was made by changing the name of the Regenkreis to the “Kreis Oberpfalz und Regensburg” [District of the Upper Palatinate and Regensburg], now “Oberpfalz”.