Bludau was formerly part of the German Empire. In the German Empire, the place was called Bludau.
The place is now called Kostrovo and belongs to Russian Federation.
| Historical place name | Country | Administration | Time |
|---|---|---|---|
| Bludau | German Empire | Samland | 1939 |
| Bljudau | Under Soviet administration | Kaliningrad | 1945 |
| Kostrovo | Russian Federation | Zelenogradsk | 1992 |