Rhenish Prussia (Ger. Rheinland, or Rhein-preussen), the most western and most thickly peopled of the provinces of Prussia, lies on the Rhine and Lower Moselle, and is bounded W. by Luxemburg, Belgium, and the Netherlands. Long and narrow, it extends from Cleves in the north to Saargemund in the south, and contains Cologne, Aix-la-Chapelle (Aachen), Treves, Coblenz (the capital), Elberfeld-Barmen, Essen, Bonn, Dussel-dorf, and Crefeld. Area, 10,419 sq. m.; pop. (1885)4,344,527; (1900) 5,759,798, of whom 4,400,000 were Roman Catholics and 15,000 Walloons. The surface is everywhere more or less mountainous, except in the extreme north, reaching 2500 feet on the west of the Rhine, but only 1800 on the east side. The valleys of the Rhine, Moselle, and Nahe are very fruitful, and so are the flat districts in the north. Of the total area, 64 per cent. is cultivated, including meadows and vineyards, and nearly 31 per cent. under forest. More than sixteen million tons of coal are mined in the year, also large quantities of iron, zinc, and lead ore. The sulphur-springs of Aix-la-Chapelle and Burt-scheid have a European reputation. Industry and manufactures are prosecuted with the greatest energy and success, this province ranking first in all Prussia in this respect. It was formed in 1815 out of the duchies of Cleves, Julich (Juliers), Guelders, Berg, etc.