city, just northeast of Bilbao, Vizcaya provincia (province), in the comunidad autónoma (autonomous community) of Basque Country, northern Spain. The city, on the Río de Plencia (Butrón) near the inlet of the Bay of Biscay (Biscay, Bay of), is the statutory capital of the former lordship of Vizcaya, sacred to the Basques. It is symbolized by a venerable oak, the Guernikako arbola (tree of Guernica), under the branches of which the batzarraks (councils) of Vizcaya met to determine defense policies and to receive royal assurances of fueros (charters of privileges), which were retained from the Middle Ages through the 19th century. In 1366 Count Tello organized Guernica as an enclave, autonomous from the surrounding district of Luno, a status that endured until 1882, when Guernica and Luno were united as a municipality.

After surviving the Carlist Wars of the 19th century, Guernica led the futile agitation for an independent Basque state in 1932. On April 27, 1937, the city was heavily bombed, supposedly by German planes, an incident that inspired Pablo Picasso's famous painting Guernica (1937). The city's architectural highlights include the Council or Parliament House (1824–33), the Tribunales (law courts), and the church of Santa María la Antigua (1418).

Industries include food processing, furniture making, metalworking, and ammunition manufacturing. Tourism is an added source of income. Pop. (2007 est.) mun., 16,171.