Fuerte de Cobos, Military fortress in Campo Santo, Argentina

Fuerte de Cobos is an adobe military fortress with a square structure of about 100 meters per side, featuring defensive bastions at two opposite corners of the compound. A two-story central building with balconies overlooks the interior spaces.

The outpost was founded as Nuestra Señora de Santa Ana on 26 August 1690 by Salta's lieutenant governor Diego Diez Gómez, after Governor Tomás Félix de Argandoña decided to fortify it against Gran Chaco raids. Governor Juan de Armasa y Arregui rebuilt it in 1733, a date recorded on the entrance lintel. In 1775 an indigenous invasion burned it down. On 14 February 1813 Belgrano retook it by surprise shortly before the Battle of Salta.

The fortress displays Spanish military architecture with two-story structures and balconies that still define the colonial defensive layout today. This building style was typical for outposts meant to protect Salta from attacks.

The fortress is located in a valley between rivers and is reachable via a road near National Route 9. Visitors should be aware it is a historic structure in rural countryside and should bring appropriate gear.

In 1772 the postal inspector Alonso Carrió de la Vandera set up a posta at the fort while laying out the mail route between Buenos Aires and Lima. His companion, the Cuzco native Calixto Bustamante Carlos, wrote under the pen name Concolorcorvo that the fort's house was so ruined that climbing its staircase was an effort.