Seven Island Lake Nature Reserve
| Seven Island Lake Nature Reserve | |
|---|---|
| Rezerwat przyrody Jezioro Siedmiu Wysp | |
IUCN category IV (habitat/species management area) | |
| Location | Warmian-Masurian Voivodeship, Poland |
| Coordinates | 54°18′N 21°34′E / 54.300°N 21.567°E |
| Area | 10.06 km2 (2,490 acres) |
| Established | 1956 |
| Official name | Lake of Seven Islands Nature Reserve |
| Designated | 3 January 1984 |
| Reference no. | 285 |
Seven Island Lake Nature Reserve (Polish: Rezerwat przyrody Jezioro Siedmiu Wysp) is a nature reserve established in 1956 around Oświn Lake in north-eastern Poland, close to the border with the Kaliningrad Oblast of Russia.