Koszajny was formerly part of the German Empire. In the German Empire, the place was called Koschainen.
The place is now called Koszajny and belongs to Poland.
| Historical place name | Country | Administration | Time |
|---|---|---|---|
| Koschainen | German Empire | Mohrungen | 1939 |
| Koszajny | Under Polish administration | Morąg | 1945 |
| Koszajny | Poland | Olsztyn | 1992 |