I have not been able to find any evidence from either the novels or the World of Ice and Fire that explicitly states that Kingsgrave, the seat of House Manwoody is in the Prince’s Pass. Why would the Fowlers want to share in the riches that flow into their coffers from the trade passing though their pass? – “so the Fowlers took for themselves the grandiose titles of Lords of Skyreach, Lords of the Wide Way, and Kings of Stone and Sky.”