Pays de la Loire (French pronunciation: [pe.i də la lwaʁ]; Breton: Broioù al Liger) is one of the 18 regions of France. It is one of the regions created in the 1950s to serve as a zone of influence for its capital, Nantes, one of a handful so-called "balancing metropolises" (métropoles d'équilibre)¹. Other examples of "artificially created" regions include Rhône-Alpes, which was created as the region for Lyon, and Midi-Pyrénées, which was created as the region for Toulouse.
Thus the name of the region, chosen by the French central government, was not based on history, but purely on geographical references: Pays (i.e., "lands") de la Loire (i.e. "of the Loire River"). The majority of the famous châteaux of the Loire Valley are located in the Centre region, and not inside Pays de la Loire, despite the apparent reference to the river in the name.
¹ In the 1960s, eight large regional cities of France (Lille, Nancy, Strasbourg, Lyon, Nantes, Bordeaux, Marseille, Toulouse) were made "balancing metropolises", receiving special financial and technical help from the French government in order to counterbalance the excessive weight of Paris inside France.