This list of historical markers installed by the National Historical Commission of the Philippines (NHCP) in Cagayan Valley (Region II) is an annotated list of people, places, or events in the region that have been commemorated by cast-iron plaques issued by the said commission. The plaques themselves are permanent signs installed in publicly visible locations on buildings, monuments, or in special locations. This article lists thirty-four (34) markers from the Region of Cagayan Valley.