Kojdy was formerly part of the German Empire. In the German Empire, the place was called Koiden.
The place is now called Kojdy and belongs to Poland.
| Historical place name | Country | Administration | Time |
|---|---|---|---|
| Koiden | German Empire | Osterode i. Ostpr. | 1939 |
| Kojdy | Under Polish administration | Ostróda | 1945 |
| Kojdy | Poland | Olsztyn | 1992 |