Stein () is a municipality in the district of Rheinfelden in the canton of Aargau, Switzerland.
The town lies across the Rhine River from Bad Säckingen in the German state of Baden-Württemberg. Two bridges link the two city, one vehicular (Fridolinsbrücke) and the other, the Holzbrücke pedestrian bridge.
The Stein-Säckingen railway station is located in Stein.
Geography
thumb|left|Hydroelectric power plant that crosses the Rhine from Bad Säckingen (Germany) and Stein (Switzerland)
thumb|left|Aerial view (1949)
Stein has an area, , of . Of this area, or 28.5% is used for agricultural purposes, while or 22.1% is forested. Of the rest of the land, or 39.1% is settled (buildings or roads), or 10.3% is either rivers or lakes.