It was in 1998 when the Aparri Sub-Office (APSO) was established. It started at Rizal Street, Aparri Cagayan but was transferred to CAGELCO II Main Office in 1992. It supplies 4 towns namely Aparri, Camalaniugan, Lallo and Calayan Island lighting up 108 barangays.

Lallo Action Center (LAC) located at Bagumbayan, Lallo was established in 1998 to assist the Coop in its Collection and accommodate the complaints/requests of the Member Consumers.

The Bantay Substation at Bantay, Camalaniugan and the Magapit Sub Station are the power suppliers to the said municipalities. Similar with other sub-offices, APSO also holds two districts: District IV – Aparri and District V – Camalaniugan, Lallo, and Allacapan.

APSO serves a total of 24, 540 households as of December 2014.