Koźlak was formerly part of the German Empire. In the German Empire, the place was called Wilhelmshöh.
The place is now called Koźlak and belongs to Poland.
| Historical place name | Country | Administration | Time |
|---|---|---|---|
| Wilhelmshöh | German Empire | Angerburg | 1939 |
| Koźlak | Under Polish administration | Węgorzewo | 1945 |
| Koźlak | Poland | Suwałki | 1992 |