Hercules III (b. 1727 – d.1803) is the Duke of Modena and Reggio Emilia from 1780 to 1796.
His main activities are to continue the jurisdiction policy started by his father Francis III and the rebalancing of the financial disarray of the State.
The voluntary adherence of Reggio Emilia to the Estensi Family dates back to 1409 when the town, a free Municipality at that time, entrust to Nicolò d’Este with special agreements granting its rights.