The city is part of an "arrondissement" (a part of a department) with the same name, along the northern border with the Dominican Republic. The Dajabón River is between Ouanaminthe and the Dominican city of Dajabón. The border crossing to Dajabón is one of the four chief land crossings from Haiti to the Dominican Republic and Haitians living in Ouanaminthe are allowed to cross the border to Dajabón only two days per week.