Quirino

Quirino, officially known as the Province of Quirino (Filipino: Lalawigan ng Quirino) is a landlocked province of the Philippines. It is located in the Cagayan Region and is bordered by the provinces of Isabela to the north, Nueva Vizcaya to the west, and Aurora to the southeast. Its capital and largest city is Cabarroguis, located in the north of the province.

The province has a population of 230,641, and a population density of 99 people per square kilometer.

Geography
Quirino province is at the southern edge of the Cagayan River basin. It is dominated by the Sierra Madre Mounains in the southeast and the Caraballo Mountains in the west. The province's highest peak is Mount Otunao at 1464 meters above sea level.

It is the only province with completely straight borders.