The Treviño Enclave in northern Spain is part of the territory of the province of Burgos, but is completely surrounded by the territory of the Basque Country province of Álava. Thus, it is an enclave of the Basque Country and an exclave of Castile and León. It consists of two municipalities—Condado de Treviño and La Puebla de Arganzón—and is part of the Judicial district of Miranda de Ebro in the province of Burgos.

Álava or Araba, officially Araba/Álava, is a province of Spain and a historical territory of the Basque Country, heir of the ancient Lordship of Álava, former medieval Catholic bishopric and now Latin titular see.