Hai Hau district, the newly formed over five centuries ago, is a coastal district of Nam Dinh province. This land is made up of solidarity, self-reliance, hard-working "sea-dykes" of "four first settlers - nine families" and descendants of generations. Since 1978, Hai Hau has been continuously admitted one of informative and cultural districts of Viet Nam for 36 years. The article, based on reliable historical evidence, writes about the "sea-dykes" process of forming the district of "four first settlers - nine families" as well as the beauty of Hai Hau people for over five centuries.