About this sound Zhoushan ; formerly transliterated as Chusan, is a prefecture-level city in northeastern Zhejiang province of Eastern China. One of the two prefecture-level cities of the People's Republic of China consisting solely of islands (the other is Sansha in Hainan, however its territory is in dispute), it lies across the mouth of the Hangzhou Bay, and is separated from the mainland by a narrow body of water.