Sunrise over Thomsen Harbor in Alaska The City and Borough of Sitka is a unified city-borough located on the west side of Baranof Island in the Alexander Archipelago of the Pacific Ocean part of the Alaska Panhandle, in the U S state of Alaska With an. Sunrise over Thomsen Harbor in Alaska The City and Borough of Sitka is a unified city-borough located on the west side of Baranof Island in the Alexander Archipelago of the Pacific Ocean part of the Alaska Panhandle, in the U S state of Alask