| Frederick IX | |
|---|---|
| Margrave of Brandenburg | |
_-_Frederick_of_Brandenburg.jpg) Margrave Frederick IX of Brandenburg | |
| Born | 22 March 1588 Cölln |
| Died | 19 May 1611 (aged 23) Słońsk |
| Burial | Parish church of Küstrin |
| House | Hohenzollern |
| Father | John George, Elector of Brandenburg |
| Mother | Elisabeth of Anhalt-Zerbst |
Frederick IX of Brandenburg (22 March 1588 in Cölln – 19 May 1611 in Sonnenburg, Prussia (now Słońsk, Poland)) was a Margrave of Brandenburg.