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