INSTERBURG, a city of the circle of the same name in the Gumbinen division of the province of East Prussia. It stands near the junction of the river Angerap with the Inster, by which the navigable river Pregel is formed. It contains two churches, 465 houses, and 5870 inhabitants. There are some manufacturers of cloth, linen, and hosiery. It is the seat of the several courts of justice for the ancient districts, which were a part of Lithuania. Lat. 54° 37' 16"; Long. 21° 34' 1" E.