The Treviño Enclave ( ) in northern Spain is part of the territory of the province of Burgos (part of Castile and León), 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 (partido judicial) of Miranda de Ebro in the province of Burgos. The enclave consists of the municipalities of Condado de Treviño, with an area of and a 2009 population of 1,432, giving it a population density of and La Puebla de Arganzón, with an area of and a 2009 population of 529, giving it a population density of . This gives the enclave as a whole an area of and a 2009 population of 1,961, for a population density of . History La Puebla de Arganzón obtained its founding fueros from Sancho VI of Navarre ("Sancho el Sabio", "Sancho the Wise") in 1191. The original fuero of Condado de Treviño is lost, but is believed to have been granted by the same king in 1161. In 1200, it was conquered by Alfonso VIII of Castile. After Castile conquered Álava, most of the region was left under the relatively egalitarian fueros typical of the Basque Country. Treviño was not. First a royal seigneury, Treviño de Uda and its outlying villages were granted in 1366 to the noble . In 1453 Diego Gómez Manrique de Lara y Castilla became a count, hence the Condado [County] de Treviño. His son became in 1482, a title that continues in the family down to the present day. In the 16th century these Counts of Treviño, Dukes de Nájera since 1593, built a palace at Treviño, which is now the ayuntamiento (town hall) of the municipality. As a result, Treviño remained closely tied to Castile. The enclave of Treviño was one of the few enclaves preserved in the 1833 territorial division of Spain, an island of Old Castile in the midst of Álava. That arrangement of the territory of Spain remains largely in effect today, although the province of Burgos is now part of Castile-León rather than the historic region of Old Castile. Current status of the enclave The status of the enclave of Treviño has long been the subject of bitter contention between the