Rheinfelden is a city and municipality of the canton of Aargau in Switzerland, seat of the district of Rheinfelden. It is east of Basel. The name means the fields of the Rhine, as the town is on the Hochrhein. It is home to Feldschlösschen, the most popular beer in Switzerland. The city is across the river from Rheinfelden in Baden-Württemberg; the two cities were joined until Napoleon Bonaparte fixed the German–Swiss border on the Rhine in 1802 and are still socially and economically tied.