Pregolya basin

The Pregolya or Pregola (; ; ; ) is a river in the Russian Kaliningrad Oblast exclave.

thumb|Deyma The Deyma (; ; ) is a river in Russia's Kaliningrad Oblast. It separates from the Pregolya at Gvardeysk, flows through Polessk, and ends at the Curonian Lagoon. The Polessk Canal connects the Deima with the Nemunas.