LAWENBURG, Duchy of, a territory of Germany, in the circle of Lower Saxony, bounded by the duchy of Holstein on the north and west, by the duchy of Mecklenburg on the east, and by the duchy of Lauenburg, from which it is separated by the river Elbe, on the west; being about 85 miles long, and 20 broad. The chief towns are Lawenburg, Molen, Wittemberg, and Ratzeburg. It came into the possession of Denmark in 1815.