RONSDORF, a town of Prussia, in the province of the Rhine, and government of Düsseldorf, on the slope of a hill on the Morsbach, 17 miles E. of Düsseldorf. It has manufactures of cutlery, silk, linen, cotton, and woollen fabrics, ribands, &c. The town owes its origin to a religious sect in the eighteenth century. Pop. 7302.