BERG, a duchy of Germany, in the circle of Westphalia. It is bounded on the north by the duchy of Cleves, on the west by the county of Mark and the duchy of Westphalia, on the south by Wetteravia, and on the east by the diocese of Cologne, from which it is separated by the Rhine. It is about 130 miles in length, and 24 in breadth. It is very fruitful along the Rhine, but mountainous and woody towards the county of Mark. It is subject to the elector palatine, but his right is disputed by Prussia and Saxony. The principal town is Dusseldorf; and the principal rivers, besides the Rhine, are the Wipper, Agger, and Sieg.