Pregolya (
Russian ???????), also spelt as
Pregola (
German Pregel,
Lithuanian Prieglius) is a river in the
Russian exclave of
Kaliningrad.
It starts as a confluence of the Instruch and the Angrapa and drains into the Baltic Sea through Vistula Lagoon. Its length under the name of Pregolya is 123&_160;km, 292&_160;km including the Angrapa. The basin has an area of 15,500 km². The average flow is 90 m³/s.
Euler's Seven Bridges of Königsberg problem was based on the rivers' bridges in what is now Kaliningrad.
pan id="coordinates">Coordinates 54°41'N 20°23'E? / ?54.683, 20.383
