Thái Bình is a coastal eastern province in the Red River Delta region of northern Vietnam. Its name is chữ Hán (太平) for "great peace." It is about 18 km from Nam Định, 70 km from Haiphong, and 110 km from Hanoi. As of 2021, it had a population 2,196,442.

Haiphong is the third-largest city in Vietnam and is the principal port city of the Red River Delta. The municipality has an area of 1,526.52 km2 (589.39 sq mi), consisting of 8 urban districts and 7 rural districts. Two of the rural districts cover islands in the South China Sea: Bạch Long Vĩ and Cát Hải. It has a population of 2,359,000 in 2021. The city's economy has strength in manufacturing, as evident by large industrial parks and numerous smaller traditional handicraft villages. Historically, Haiphong is the first place in Vietnam and Mainland Southeast Asia to get electricity.