in progress in Bingzhou (丙州) Peninsula (formerly, island) of the Dongzui Bay Tong'an District is almost coterminous with the basin of the
Xixi River ("Western Stream"), the largest river of Xiamen City. The Xixi starts in the Zhaijianwei Mountains (寨尖尾山 Zhàijiānwěishān) in the northwestern part of Tong'an District, and flows in the general south-eastern direction. After receiving a number of tributaries - Lianhuaxi (莲花溪, Lotus Stream), Aoxi (), Tingxi (), it merges with the Dongxi (东溪, Eastern Stream) at the place called Suangxikou (双溪口, "The confluence of two streams). The Xixi's estuary opens into the Dongzui Harbor (东咀港), which is a bay of
Taiwan Strait mostly enclosed by Tong'an District and
Xiang'an District on the mainland (on the northwest and east, respectively) and by the
Xiamen Island in the south. A number of large bridges have been constructed across the Xixi estuary, carrying roads and a railway between Tong'an and Xiang'an Districts (and, viewed on a larger scale, between Xiamen and
Quanzhou). ==History==