It is the center of the Klettgau historical region stretching across the Swiss border into the cantons of Aargau, Schaffhausen, and Zürich.

The municipal area includes the villages of Bühl, Erzingen, Geißlingen, Grießen, Rechberg, Riedern am Sand, and Weisweil.

The neighbouring German municipalities are Wutöschingen, Lauchringen, Küssaberg, and Hohentengen am Hochrhein in the west, as well as Dettighofen in the east.

The municipal area comprises the villages of Bühl, Erzingen, Geißlingen, Grießen, Rechberg, Riedern am Sand, and Weisweil.

Erzingen was already mentioned as villa Arcingen in an 876 deed, a Swabian possession held by the Benedictie abbey of Rheinau.

Seats in the municipal assembly (Gemeinderat) as of 2009 local elections: Population development:[3] Klettgau has a railway station located very close to the border with Switzerland, in Erzingen.

The railway line from Erzingen to Schaffhausen was electrified and tracks along almost the entire route were doubled, allowing for more frequent services to run.