RATHENAU, a city of Prussia, in the province of Potsdam, and circle of West Havell. It stands on the river Havell, is surrounded with walls, and has a good market-place, in which there is a statue of the elector Frederick William, placed to commemorate a victory gained by him near this place over the Swedes in the year 1675. It contains 620 houses, and about 4500 inhabitants.