Thái Bình

The low-lying land of Long Hưng lies amid the rivers and rice fields of the southern Red River delta. It was closely associated with the Trần royal family, whose tombs were established here in their ancestral country. During the Mongol invasions of the thirteenth century, Long Hưng and neighbouring Kiến Xương also formed a defensive base, with waterways, barriers and fortified positions supporting the Trần resistance.

The later city of Phủ Lý lies here.