a ▁province ; ▁on ▁the ▁west ▁by ▁the ▁Cord ill era ▁Mountains ; ▁and ▁on ▁the ▁north ▁by ▁the ▁Bal int ang ▁Channel ▁and ▁the ▁Bab uy an ▁Group ▁of ▁Islands . ▁About ▁ ▁from ▁the ▁n ort he astern ▁tip ▁of ▁the ▁province ▁is ▁the ▁island ▁of ▁Pal au i ; ▁a ▁few ▁kilom eters ▁to ▁the ▁west ▁is ▁F uga ▁Island . ▁The ▁Bab uy an ▁Group ▁of ▁Islands , ▁which ▁includes ▁Cal ay an , ▁Dal up iri , ▁Cam igu in , ▁and ▁Bab uy an ▁Cl aro , ▁is ▁about ▁ ▁north ▁of ▁Lu zon ▁main land . ▁ ▁The ▁eastern ▁coast ▁forms ▁the ▁northern ▁portion ▁of ▁the ▁Sierra ▁Mad re ▁mountain ▁range , ▁while ▁the ▁western ▁limits ▁are ▁generally ▁h illy ▁to ▁low ▁in ▁elev ation . ▁The ▁central ▁area , ▁domin ated ▁by ▁a ▁large ▁valley , ▁forms ▁the ▁lower ▁bas in ▁of ▁the ▁country ' s ▁longest ▁river , ▁the ▁C ag ay an . ▁The ▁mouth ▁is ▁located ▁at ▁the ▁northern ▁town ▁of ▁A par ri . ▁ ▁The ▁province ▁of ▁C ag ay an ▁compr ises ▁an ▁aggregate ▁land ▁area ▁of ▁ ▁which ▁constit utes ▁approximately ▁three ▁percent ▁of ▁the ▁total ▁land ▁area ▁of ▁the ▁country , ▁making ▁it ▁the ▁second ▁largest ▁province ▁in ▁the ▁region . ▁ ▁Administr ative ▁divisions ▁C ag ay an ▁compr ises ▁ 2 8 ▁municipal ities ▁and ▁one ▁city ▁divided ▁into ▁three ▁con gression al ▁districts . ▁It ▁has ▁ 8 2 0 ▁bar ang ays .