Haiphong or Hai Phong is the smallest municipality of Vietnam by area and is the principal port city of the Red River Delta, with an area of 3,194.72 km2 (1,233.49 mi2). It includes Bạch Long Vĩ and Cát Hải islands in the Gulf of Tonkin. Haiphong has a population of 4,664,124 in 2025.