History of Udondo Bridge

One of Bizkaia’s greatest industrial heritage gems – Udondo Bridge – stands very close to the Leioa Metro underground stop, where the Udondo and Gobela rivers flow into the Nervión-Ibaizabal river estuary. It is longest surviving bridge of the many that Bilbao had; it was the first iron bridge built in Spain and also the oldest of the ones to be found today; it is also one of the few cast-iron bridges still existing outside the British Isles.

Built in 1846-47, it was dismantled from its original location in Bilbao and relocated in Leioa in 1876 to place the stone bridge that stood there until it was blown up by Carlist troops.

Go to content

A bit of history

  • The Udondo Bridge, located over the Udondo and Gobela rivers, on the border between Erandio and Leioa, on the road from Bilbao to Las Arenas, has a history dating back to 1844, when architect Antonio de Goicoechea submitted a project to Bilbao City Council to build an iron bridge connecting the historic town, now the Casco Viejo, with the new Ensanche district that was about to be built and, above all, with the railway station.

    A Royal Order approved the project, and construction began in 1845, opening in January 1848 under the name of the “Isabel II Bridge”.

  • In addition to three smaller arches, the bridge had a central drawbridge section and four cast-iron arches with a span of 11 metres. It was one of the first major works of the Santa Ana de Bolueta factory, Bilbao. It was similar in some respects to the Triana Bridge that was being built in Seville and which was unveiled three years after the one in Bilbao.

  • During the Carlist War and the siege of Bilbao in 1874, several bridges in the area were damaged, including the old stone bridge over the Udondo in Leioa and the Isabel II Bridge, or Arenal Bridge. In 1876, construction work began on a new bridge in the Arenal district of Bilbao, which involved the demolition of the remains of the previous one.

    That year, at the June municipal plenary session of Bilbao City Council, a letter signed by the Chief Engineer of Obras Públicas of Vizcaya, Pascual Landa, was read out, proposing that “it might be convenient and economical for the State to acquire the knife plates from one of the iron arches, as they could be used in the reconstruction of the ‘Udondo’ bridge on the towpath from this city to Las Arenas, which is a pressing matter”. Bilbao City Council agreed to this.

  • In the mid-20th century, the road from Bilbao to Las Arenas was widened, and this piece of history was covered a concrete structure, which has, in a way, protected it to this day.