ROSSLAU, a town of Germany, in the duchy of Anhalt, on the right bank of the Elbe, here crossed by two railway bridges, 3 m. by rail N. of Dessau and 35 m. S.E. of Magdeburg. Pop. (11905) II, O27. It has a ducal residence, an old castle, a handsome parish church, and manufactures of machinery, paper, sealing-wax, wire goods, sugar, bricks and chemicals. Rosslau became a town in 1603.