 The harbor faces the Zambales Mountain Range to the west and the Subic Bay opening to the South China Sea.Subic Bay is surrounded by the town of Subic and Olongapo City, both in the province of Zambales, and Morong in the province of Bataan.Development of Olongapo City was largely tied to the presence of the United States Navy base, once the largest U.S. military naval base in Asia.