Hải Dương was a former province in the Red River Delta of northern Vietnam. Its name derives from Sino-Vietnamese 海陽 "ocean sun", though the modern province is in fact landlocked. Located in the Northern Key Economic Region, Hai Duong Province has a dynamic economy with a focus on industrial manufacturing.
On June 12, 2025, Hải Dương was incorporated into Haiphong.
Thái Bình river (Vietnamese: Sông Thái Bình) is the name of the Thái Bình river system's main river in Northern Vietnam. This river system joins with the Red River system and brings alluvium to create Red River Delta.
Thái Bình river starts in the area of Đồng Phúc commune, Yên Dũng District, Bắc Giang Province – where the Thuong River and Cầu River join with each other. It then flows to Hải Dương Province and becomes the boundary between Bắc Giang and Hải Dương. After flowing through the area of Hải Dương, it enters Thái Bình Province and flows to the South China Sea at Ba Lat river mouth.
Hải Dương () was a city in Vietnam. It was the capital of Hải Dương, an industrialized province in the Hanoi Capital Region and the Red River Delta in Northern Vietnam, now merged into Haiphong. The city is at the midpoint between the capital Hanoi and the major port Haiphong, and is part of the Northern Key Economic Zone. In 2019, Hai Duong city had a population of 241,373.