The 1st Army Division (Spanish: I División de Ejército), formerly the Northern Army Detachment (Spanish: Agrupamiento del Norte), is a combined infantry division unit of the Peruvian Army (EP) that specialized in combat patrol in mountain forest terrain, combined arms, counterinsurgency, jungle warfare, and maneuver warfare.

First founded as a Region, its headquarters were relocated by Luis Miguel Sánchez Cerro's administration from Lambayeque to Piura in 1930.

[3] It was then reorganized under Manuel Prado's administration and renamed as the Northern Army Detachment (Spanish: Agrupamiento del Norte) in January 1941, under the command of then General Eloy Ureta.

[4] After hostilities broke out with Ecuador on July of the same year, the division took on a major role during the conflict, carrying out an offensive on the Ecuadorian coast.

[8] The 1st Army Division is formed by the following units:[9]