Allacapan is a 3rd class municipality located on the northwestern side of Cagayan Province. It is bounded on the
north by Ballesteros town, on the east by Camalaniugan and Lal-lo, on the south by Lasam, and on the west by Apayao Province.
It has a total land area of 306 square kilometers and is politically subdivided into 27 barangays.
The town is situated 94 kilometers north of Tuguegarao City, the provincial capital.
