San Sebastián, officially known by the bilingual name Donostia / San Sebastián, is a city and municipality located in the Basque Autonomous Community, Spain. It lies on the coast of the Bay of Biscay, 20 km from the France–Spain border. The capital city of the province of Gipuzkoa, the municipality's population is 188,102 as of 2021, with its metropolitan area reaching 436,500 in 2010. Locals call themselves donostiarra (singular), both in Spanish and Basque. It is also a part of Basque Eurocity Bayonne-San Sebastián.

The Basque Country, also called the Basque Autonomous Community, is an autonomous community in northern Spain. It includes the Basque provinces of Álava, Biscay, and Gipuzkoa. It also surrounds an enclave called Treviño, which belongs to the neighboring autonomous community of Castile and León.