The area, once part of Peru, was captured by Chilean forces in the War of the Pacific by its namesake and commander of Chilean troops in the Battle of Arica, General Pedro Lagos.

According to the 2002 census of the National Statistics Institute, General Lagos had 1,179 inhabitants (761 men and 418 women), all listed as living in rural areas.

[2] As a commune, General Lagos is a third-level administrative division of Chile administered by a municipal council, headed by an alcalde who is directly elected every four years.

Within the electoral divisions of Chile, General Lagos is represented in the Chamber of Deputies by Nino Baltolu (UDI) and Orlando Vargas (PPD) as part of the 1st electoral district, which includes the entire Arica and Parinacota Region.

The commune is represented in the Senate by Fulvio Rossi Ciocca (PS) and Jaime Orpis Bouchon (UDI) as part of the 1st senatorial constituency (Arica and Parinacota Region and Tarapacá Region).