William I, Elector of Hesse
| William I | |
|---|---|
| Elector of Hesse | |
Portrait by Wilhelm Böttner, c. 1795 | |
| Landgrave of Hesse-Kassel | |
| Reign | 31 October 1785 – 27 February 1821 |
| Predecessor | Frederick II |
| Successor | William II |
| Born | 3 June 1743 Kassel, Hesse-Kassel, Holy Roman Empire |
| Died | 27 February 1821 (aged 77) Kassel, Hesse, German Confederation |
| Spouse | |
| Issue among others... | |
| House | Hesse |
| Father | Frederick II, Landgrave of Hesse-Kassel |
| Mother | Princess Mary of Great Britain |
| Religion | Calvinist |
William I, Elector of Hesse (German: Wilhelm I., Kurfürst von Hessen; 3 June 1743 – 27 February 1821) was the eldest surviving son of Frederick II, Landgrave of Hesse-Kassel (or Hesse-Cassel) and Princess Mary of Great Britain, the daughter of George II.