United States Logistics Group (TUSLOG) Det-12 Istanbul was a U.S. Naval Security Group Activity (NSGA), first established in October, 1952 and was in continuous operation until June 30, 1965 until it permanently closed. The installation was located on a Turkish Naval base on the Asian side of the Bosphorus. The Det-12 installation consisted of two quonset huts located on the waterfront and the operations site, which was located on top of a 600 foot hill overlooking the northern entrance of the Bosphorus, into the Black Sea. The operations site on the hill consisted of a small operations building (4 or 5 rooms), an administrative building (one room) and a generator building. There was also an ancient castle located on the hill about 150 yards from the operations building.