Rheinfelden (, ) is a municipality in the canton of Aargau in Switzerland, seat of the district of Rheinfelden. It is located 15 kilometres east of Basel. The name means the fields of the Rhine, as the town is located on the High Rhine. 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 Germany–Switzerland border on the Rhine in 1802 and are still socially and economically tied. Geography The old town of Rheinfelden lies on the left bank of the Rhine, where the river is divided into two arms by the "Inseli", a roughly long island. Downstream of the Inseli and the Rheinbrücke, the river bottoms drops to about deep, creating a huge and deadly vortex, known as the St-Anna-Loch. Nearly east is the Magdenerbach. The wooded, gently-rising foothills of the Tafeljura lie south of the town. These are the Steppberg (above sea level) and the "Berg" (), both in the south-east. Between these two hills lie the deeply incised valleys of the Magdenerbach. Rheinfelden has an area, (as of the 2004/09 survey) of . Of this area, about 20.7% is used for agricultural purposes, while 50.0% is forested. Of the rest of the land, 22.6% is settled (buildings or roads) and 6.7% is unproductive land. In the 2013/18 survey a total of or about 13.3% of the total area was covered with buildings, an increase of over the 1982 amount. Over the same time period, the amount of recreational space in the municipality increased by and is now about 3.43% of the total area. Of the agricultural land, is used for orchards and vineyards, is fields and grasslands. Since 1982 the amount of agricultural land has decreased by . Over the same time period the amount of forested land has increased by . Rivers and lakes cover in the municipality.Regionalporträts 2017: Swiss Federal Statistical Office accessed 18 May 2017 The highest point () is located on "Berg", the lowest point () is on the Rhine. Neighbouring cities are Kaiseraugst to the west, Olsberg to the south-west, Magden to the south and Möhlin to the east (all in the Aargau); over the river in Germany lies Rheinfelden, Baden-Württemberg. History The area around Rheinfelden was already settled in the Middle Stone Age, around 10,000 years before the present day.