Cárcel de San Fernando, Historical Monument in San Fernando, Chile.

Cárcel de San Fernando is a prison building in San Fernando designed with an octagonal center that connects two separate wing sections on multiple levels. The structure features exposed brick walls that are quite thick, following the construction methods used for such institutions during that era.

The prison was built in 1891 during President Balmaceda's time in office and became part of the city's growth and modernization. Its construction reflected Chile's efforts to develop urban infrastructure with new public buildings during that period.

The building mixes neoclassical elements in its northern administrative area with industrial architecture in its southern cell blocks, showing how institutions were designed in the late 1800s. Walking through, you notice how these two contrasting styles sit side by side within the same structure.

The building occupies a full block of the founding grid, with its main access and one-storey administrative section facing north and the two-level cell block to the south. The 1985 earthquake left structural fractures in several walls, so the exterior is best viewed from the street. The site lies within the urban centre of San Fernando, near the Regimiento Colchagua.

The 1985 earthquake fractured several of the prison's walls, and the building stayed in a poor state of conservation for decades. Its 2009 declaration as a National Historic Monument came after years of this deterioration, not before.