Tien Hai Wetland Nature Reserve

Between two wide river mouths, where the Red River has branched and then runs out into the sea, lies a stretch of land that is neither mountain forest nor white sand. It is made of silt, salt marsh and tides that rise and fall, built up year by year from the mud the river carries. People call it the Tiền Hải Wetland Nature Reserve.

The reserve lies outside dikes number five and number six, in the old Tiền Hải area. To the north it reaches the Trà Lý river mouth. To the south it reaches the Ba Lạt river mouth, and to the east it meets the sea. In 2025 the provinces of Thái Bình and Hưng Yên merged under a resolution of the National Assembly. Since then the reserve has stood inside Hưng Yên province.

The reserve covers 12,500 hectares. It holds thousands of hectares of mangrove forest, mixed with mudflats and wide wetland. In 2024 its boundary was set down again, marked out by 33 coordinate points, and the total area stayed the same.

Inside that boundary are three different zones. The strictly protected zone covers 2,726 hectares. It is the heart of the reserve, where the habitat is kept almost whole. The ecological recovery zone covers 9,774 hectares and is land that is coming back to life. The buffer zone, at 3,446.5 hectares, wraps around the outside.

This land is a core area of the Red River Delta Biosphere Reserve. A biosphere reserve is a UNESCO-recognized area where nature is protected and the people living there keep working the land. The other core area is Xuân Thủy National Park, in the old Nam Định province, now part of Ninh Binh. The biosphere reserve takes in many kinds of habitat: river mouths, salt marsh, mudflats, beaches and seagrass. Tiền Hải is one piece of that picture that cannot be left out.

What sets this place apart is its birdsong. A survey recorded more than 150 species of waterbirds that live here or spend the winter here. Some of them are listed in Vietnam's Red Book. One is the bồ nông chân xám, a pelican. Another is the cò thìa, a spoonbill. The third is the mòng bể mỏ đen, a gull. In the migration season the sky above these mudflats becomes a flight path for tens of thousands of birds from the distant north.

A bare mudflat can hold thousands of tiny creatures living out of sight under the mud. A mangrove forest that looks still is a home for many generations of birds. And all 12,500 hectares of this land are doing quiet and enormous work: keeping life strong along the coast of northern Vietnam.