Instruch
The Instruch (Russian: Инструч; German: Inster; Lithuanian: Įsrutis; Polish: Wystruć) is a river in Russia's Kaliningrad Oblast. It develops northeast of Dobrovolsk (formerly Pillkallen, Schlossberg between 1938-1946) and, along with the Angrapa River, forms the Pregolya near Chernyakhovsk.
Prior to 1945, the river was part of German East Prussia. The town of Insterburg (now Chernyakhovsk) was named after the river's German name, Inster.
Coordinates: 54°38′52″N 21°47′27″E / 54.64778°N 21.79083°E
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