Prussia may refer to several related areas:
- The German theocratic state of the Teutonic Order on the southeastern coast of the Baltic Sea, from 1525 a secularized Duchy under Grand Master Albert von Hohenzollern and his successors.
- The Kingdom of Prussia, as it became from January 1701, continued its rule by the German Hohenzollern dynasty, at first including Prussia and Brandenburg, a principality with Berlin as its capital. Initially a part of the Holy Roman Empire, Prussia gradually expanded in size, eventually becoming the dominant part of the German Empire, with the Prussian King also being the German Emperor.
- Part of the Weimar Republic.
- The Evolution of Prussia by Sir J. A. R. Marriott, M.A., and Sir Charles Grant Robertson, C.V.O., LL.D., M.A., Revised edition, Clarendon Press, Oxford U.K. 1946.