Protection zone of the National Park stretches on the western side from the source of the Krka river and its course to the confluence with the Una on the state border of Bosnia and Herzegovina with Croatia from where park border follows the Una and state border to the town of Martin Brod and confluence with the Unac. On the eastern side border of the park goes from the entrance of the Unac River into its canyon, few kilometers downstream from town of Drvar, and follows the Unac and its canyon all the way to the confluence with the Una in town of Martin Brod. From there park border follows the Una on the right and state border between Bosnia and Herzegovina and Croatia on the left, until it reach a small town of Ripač, few kilometers upstream from town of Bihać.