Angola
| Date | Weekday | Event | Country | Type |
|---|---|---|---|---|
| 17 Sep | Wednesday | National Hero Day | Angola | Public |
| 17 Sep | Wednesday | Sybirak's Day | Poland | Not public |
| 17 Sep | Wednesday | The Day Russia Invaded Poland in 1939 | Poland | Not public |
| 17 Sep | Wednesday | Birth of the Crown Prince | Tonga | Public |
| 17 Sep | Wednesday | Citizenship Day | United States | Not public |