Del Canto's division was scattered through the southern region of the Peruvian Andes, divided into small groups stationed in several towns and enduring a severe lack of supplies including food, clothes, shoes, and ammunition, and heavy casualties from disease and the cold of these heights.
The garrison posted at Concepcion was the 4th company of the "Chacabuco" 6th Line Battalion, consisting of 77 soldiers under the command of Lieutenant Ignacio Carrera Pinto.