Vallenar, located in the valley of the Huasco river, was founded on 1789 by Don Ambrosio O`Higgins who originally called this city "San Ambrosio de Ballenary", in remembrance of his native town Ballenary in Ireland.

The Vallenar area was well known as a rich mining zone in which deposits could be found of copper, silver and iron. The mining activity contributed to the growth of the city, which consequently brought the railroad in 1892, the telephone line from Huasco to San Felix in 1909, amongst other infrastructure made in the "gold rush" for iron. The activity is also reflected in the architecture, which can be appreciated in the Church and other buildings around the town.

On the night of 10th of November 1922, a strong earthquake of approximately 8 degrees in the Richter scale affected Vallenar. This earthquake caused hundreds of victims and destroyed part of the city. The economic damage at the time was vast. The cities of Chañaral, Antofagasta and Freirina were also affected.

At the moment, the main economic activity around Vallenar is agriculture due to the quality of the soil; especially fruit growing like peaches, apricots, cherimoyas, quinces and grapes. There is also cattle ranching is the area but to a smaller degree.