Basque (endonym: Euskara, IPA: [eus̺kaɾa]) is the ancestral language of the Basque people, who inhabit the Basque Country, a region spanning an area in northeastern Spain and southwestern France. It is spoken by 25.7% of Basques in all territories (665,800 out of 2,589,600). Of these, 614,000 live in the Spanish part of the Basque country and the remaining 51,800 live in the French part.

In academic discussions of the distribution of Basque in Spain and France, it is customary to refer to three ancient provinces in France and four Spanish provinces. Native speakers are concentrated in a contiguous area including parts of the Spanish Autonomous Communities of the Basque Country and Navarre and in the western half of the French Département of Pyrénées-Atlantiques. The Basque Autonomous Community is an administrative entity within the binational ethnographic Basque Country incorporating the traditional Spanish provinces of Biscay, Gipuzkoa, and Álava, which retain their existence as politico-administrative divisions.