Zelazko was formerly part of the German Empire. In the German Empire, the place was called Zelazko.
The place is now called Żelasko and belongs to Poland.
| Historical place name | Country | Administration | Time |
|---|---|---|---|
| Żelasko | Russian Empire | Olˈkuš | 1914 |
| Żelasko | Poland | Olkusz | 1919 |
| Zelazko | German Empire | Bendzin/Bendsburg | 1939 |
| Żelasko | Poland | Olkusz | 1945 |
| Żelasko | Poland | Katowice | 1992 |