The noble and loyal town of Gernika-Lumo is a municipality belonging to the Busturialdea region and is surrounded by the natural area of Urdaibai.
The municipality of Gernika-Lumo originated in the 19th century after the administrative merging of the elizate of Lumo and the town of Gernika, in turn founded on land belonging to Lumo, although each entity preserved its own rights: the elizate the derecho foral (set of rights) of the Tierra Llana, (old administrative area); and the town, the Castilian derecho común (common right).
The town is located at 10 m of altitude in the valley of the Oca River, which forms the Gernika Estuary.
Gernika-Lumo contains the place where the representative assemblies, the so-called Juntas Generales, of Vizcaya met under the oak known as the Árbol de Gernika (tree of Gernika), symbol of the freedom of the Vizcaya people and where in the past, the ladies of Vizcaya, after receiving their title, came to swear their respect to the fuero de Vizcaya (forum of Vizcaya).
On 26 April 1937, during the Spanish Civil War, the city was bombed by the Condor Legion, a squadron of the Luftwaffe at the service of the Francoist cause. Inspired by this, Pablo Picasso painted his work Guernica which was presented at the Paris International Exhibition of 1937. In the Second World War, the Basque volunteers that participated in the Carnot Brigade of the French forces of the Interior took the name Batallón Guernica.