Imandaya : Predominantly found in Calanasan, Apayao; Carasi, Ilocos Norte; Solsona, Ilocos Norte; Barangay Cacafean, Marcos, Ilocos Norte; Barangay San Marcelino, Dingras, Ilocos Norte; Barangay Marag in Luna, Apayao; Barangay Kittag in Sanchez Mira, Cagayan; and Barangay Masi in Pamplona, Cagayan.
Imallod: Populations are spread across Kabugao, Pudtol, Flora, Santa Marcela, and Luna in Apayao.
Itawit A sub-tribe of the Isnag people, populations are distributed in the municipality of Pudtol, Apayao and some parts of Flora, Apayao.
Ingahan: A sub-tribe of the Isnag people, primarily inhabiting areas along the Nagan River in Pudtol, Apayao.
Isnag (Isneg) of Katablangan, Conner: Often spelled as Isneg due to the tribe's pronunciation, found primarily in Conner, Apayao part.
Iyapayao (Ehapayao/Yapayao): Populations are distributed in Adams, Dumalneg, Bangui, and Pagudpud in Ilocos Norte, as well as Sta. Praxedes in Cagayan.
Imalawa: An Isnag subtribe located in the outskirts of Barangay Canaam and Sitio Dasar, Barangay Isic-isic, Vintar, Ilocos Norte. The Malawa live in the village of Isic Isic, a peaceful and charming area in the Surong Valley, known for its natural beauty and friendly inhabitants.