Yingkou () is a coastal prefecture-level city of central southern Liaoning province, People's Republic of China, on the northeastern shore of Liaodong Bay. It is the third-smallest city in Liaoning with a total area of , and the ninth most populous with a population of 2,328,582 as of the 2020 census, of whom 1,228,198 lived in the built-up (or metro) area made of three urban districts (Zhanqian, Xishi and Laobian) and one county-level city (Dashiqiao). It borders the sub-provincial city of Dalian to the south, the prefectural cities of Anshan to the north and east and Panjin to the northwest, and also shares maritime boundaries with Jinzhou and Huludao across the Liaodong Bay to its west. Located on the east bank of the Daliao River mouth, Yingkou is an important port city, with the Port of Yingkou being the second-largest container port in the Bohai Sea (after the Port of Tianjin) and Northeast China (after the Port of Dalian), the tenth-largest nationwide, and the 25th-busiest worldwide. Yingkou is classified as a Medium-Port Metropolis. Name Yingkou was historically known as Newchwang (; Manchu: Ishangga gašan hoton) in postal romanization; it was one of the Treaty Ports opened under the Treaties of Tianjin of 1858. In fact, the actual town of Newchwang was about thirty miles upstream of Liao He, within today's county-level city of Haicheng. After the treaty had been signed, the British found that the river near Newchwang was too shallow for their ships. Instead, the treaty port was moved to the area nearer to the river mouth where today's Yingkou is located. To avoid confusion between the two locations, careful English writers of the early 20th century would sometimes use Newchwang for Yingkou (explaining that "Ying-kow, ... outside Manchuria, ... is known only as Newchwang") and Niu-chuang (the proper Wade–Giles transcription of '') for the actual inland Niuzhuang Town. Meanwhile, Newchwangcheng (; postal: Newchwang Town) was adopted by the government as the inland town's name to distinguish it from the coastal city. Administrative divisions Yingkou prefecture is subdivided into 4 districts and 2 cities: Geography Yingkou is mostly located in the northwestern part of the Liaodong Peninsula, and on the left bank of the mouth of Daliao River, which was historically the main distributary of the lower Liao River and the principal exit of fluvial transports from inland Liaoning into the Bohai Sea. The city's metro area is located