Mierzejewo was formerly part of the German Empire. In the German Empire, the place was called Mertenau.
The place is now called Mierzejewo and belongs to Poland.
| Historical place name | Country | Administration | Time |
|---|---|---|---|
| Mnierczeiewen | German Empire | Lötzen | 1928 |
| Mertenau | German Empire | Lötzen | 1939 |
| Mierzejewo | Under Polish administration | Giżycko | 1945 |
| Mierzejewo | Poland | Olsztyn | 1992 |