From PathfinderWiki

Deeplock is a huge stone castle in Highhelm that sits atop a gaping hole that descends into the Depths, surrounded by barracks, officers' quarters and other military structures. Deeplock is located in the northern wall of the Inner City and, from the complex, the skyseekers launch missions into the Depths. A number of lifts descend into a cave hundreds of feet below constantly guarded by elite dwarven guards.[1]