France's earliest, short-lived attempt at setting up overseas departments was after Napoleon's conquest of the Republic of Venice in 1797, when the hitherto Venetian Ionian islands fell to the French Directory and were organised as the departments of Mer-Égée, Ithaque and Corcyre. In 1798 the Russian Admiral Fyodor Ushakov evicted the French from these islands, and though France regained them in 1807, the three departments were not revived.
Under the 1947 Constitution of the Fourth Republic, the French colonies of Algeria in North Africa, Guadeloupe and Martinique in the Caribbean, French Guiana in South America, and Réunion in the Indian Ocean were defined as overseas departments. Algeria became independent in 1962 while the others are still French possessions.
Since 1982, following the French government's policy of decentralisation, overseas departments have elected regional councils with powers similar to those of the regions of metropolitan France. As a result of a constitutional revision that occurred in 2003, these regions are now to be called "overseas regions"; indeed the new wording of the Constitution gives no precedence to the terms overseas department or overseas region, though the latter is still virtually unused by the French media.
The overseas collectivity of Saint Pierre and Miquelon was an overseas department from 1976 to 1985. All five of France's overseas departments have between 200,000 and a million people each, whereas Saint Pierre and Miquelon has only about 6,000, and the smaller collectivity unit therefore seemed more appropriate for the islands.
Following a yes vote in a referendum held on 29 March 2009, the former overseas colectivity of Mayotte became an overseas department on 31 March 2011.