The Île-de-France is the most populous of the eighteen regions of France, with an official estimated population of 12,271,794 residents on 1 January 2023. Centred on the capital Paris, it is located in the north-central part of the country and often called the Paris Region. Île-de-France is densely populated and retains a prime economic position on the national stage, but it covers only 12,012 square kilometres, about 2% of metropolitan French territory. Its 2017 population was nearly one-fifth of the national total.

The crown lands, crown estate, royal domain or domaine royal of France were the lands, fiefs and rights directly possessed by the kings of France. While the term eventually came to refer to a territorial unit, the royal domain originally referred to the network of "castles, villages and estates, forests, towns, religious houses and bishoprics, and the rights of justice, tolls and taxes" effectively held by the king or under his domination. In terms of territory, before the reign of Henry IV, the domaine royal did not encompass the entirety of the territory of the kingdom of France and for much of the Middle Ages significant portions of the kingdom were the direct possessions of other feudal lords.