The Battle at Tacna was an engagement during the War of the Pacific (1879–1883) between Chile and the Allied Forces of Peru and Bolivia. It was fought on May 20, 1880, with the forces aligned as follows:
The Chilean Army was under the command of General Manuel Baquedano Gonzalez, with Colonel Velasquez as his Chief of Staff. The army was divided into five infantry divisions, with three cavalry regiments and thirty seven artillery pieces as it follows:
Strength: 2,700 men
Esmeralda Infantry Regimient (Col. Santiago Amengual) (8 companies)
Navales Infantry Battalion (Col. Martiniano Urriola) (4 companies)
Chillán Infantry Battalion (Juan Vargas Pinochet) (4 companies)
Valparaíso Infantry Battalion (Jacinto Niño) (3 companies)
Strength: 1,858 men
2nd Line Infantry Regiment (Colonel Estanislao del Canto)
Santiago Infantry Regiment (Lt. Col Francisco Barcelo)
Atacama Infantry Regiment (Lt. Col. Juan Martinez)
Strength: 1,858 men
Artillería de Marina Infantry Regiment
Coquimbo Infantry Battalion
Chacabuco Infantry Battalion
Strength: 2,285 men
Lautaro Infantry Battalion
Cazadores del Desierto Infantry Battalion
Zapadores Infantry Battalion (Lt. Col. Ricardo Santa Cruz)
Strength: 2,335 men
"Buin" 1st Line Infantry Regiment (Col. Juan Leon Garcia)
3rd Line Infantry Regiment (Col. Ricardo Castro)
4th Line Infantry Regiment (Col. Luis Solo de Zaldívar)
Granaderos Regiment (Horse Grenadiers)
Cazadores Regiment (Light Cavalry)
Carabineros de Yungay Regiment (Light Cavalry-Carabiners)
37 cannons and 4 machine guns from the 1st Artillery Regiment
Strength: 13,650 men
I Division (Col. Justo Pastor Davila)
Lima Nº 11 Battalion
Cazadores de Cuzco Battalion
II Division (Col. Andres Avelino Caceres)
Zepita Battalion
Cazadores de Misti Battalion
III Division (Col. Belisario Suarez)
Arica Battalion
Pisagua Battalion
IV Division (Col. Jacinto Mendoza)
Victoria Battalion
Huascar Battalion
V Division (Col. Alejandro Herrera)
Ayacucho Battalion
Arequipa Battalion
VI Division (Cesar Canevaro)
Lima Nº 21 Battalion
Cazadores del Rimac Battalion (Col. Víctor Fajardo)
Nacionales Division (Col. del Solar)
Formed by civilians and policemen of Tacna (the latter from the Peruvian Civil Guard)
Cavalry
Husares de Junin Squadron
Gendarmes de Tacna Squadron
Guias Squadron
Flanqueadores de Tacna Squadron
Artillery
10 cannons and 3 machine guns
I Division (Col. Severino Zapata)
Viedma Battalion
Padilla Battalion
Sucre Battalion
II Division (Col. Claudio Acosta)
Tarija Battalion
Chorolque Battalion
Grau Battalion
Loa Battalion
III Division (Col. Idelfonso Murgia)
Murillo Battalion
Alianza Battalion (known as the "Bolivian Colorados") (See also: Bolivian Colorados Regiment)
IV Division (Col. Alfonso Gonzalez)
Aroma Battalion
Cavalry
Husares Squadron
Coraceros Squadron
Artillery
6 cannons and 4 machine guns