Looking north from the road towards the formation, the Harkonnen Castle can not be mistaken as the largest and primary formation north of Owl Rock. There is an obvious splitter on the face, which is the middle section of this free climb.
Many a climber has looked over this line, but it did not see an ascent until fall 2001 by Dave Mealey and Aaron Boyles. They named the first, and currently the only, route on the formation: Dune ... after the novel by Frank Herbert. The name of the formation, although not so much a tower as a castle, is also from the the novel. The Harkonnen Castle is unlikely to provide any more decent lines, but Dune offers classic multi-pitch Arches climbing.
Getting There
Follow the main Arches road all the way to Balanced Rock. As you are passing Balanced Rock, the Harkonnen Castle is the large, long formation looking towards the La Sal mountain range. Continue past Balanced Rock and make the right turn towards the Windows section of Arches. This road follows the edge of the formation and the Harkonnen Castle becomes more obvious as it looms over the road on the right. An obvious nipple-like formation resides north and lower than the primary summit located at the south end of the tower formation. As the road wraps around the formation Owl Rock comes into view, and if you pass the Garden of Eden turnoff which leads to the Owl, you have gone too far. Park about 200 yards before the Owl Rock turn. The south face looks towards Owl Rock and the Garden of Eden parking lot.