The old Beimen District was a barrier island within Daofeng lagoon, just outside of Jishuei River river mouth. The place was called “Beimen Island” before 1920. From the maps in Local Gazetteer of Tainan Prefecture (台南縣誌), it is clear that Beimen Island existed at the river mouth of Ouwang River between the rule of Qing Dynasty Emperors Kangxi and Qianlong. However, during the Daoguang Period, Beimen Island was no longer an island and had connected with Taiwan soil. It is estimated that the transformation took place between the end of the Qianlong Period and the beginning of the Jiaqing Period.
There are two theories concerning the origins of the name “Beimen Island”. One is that the island was named thus because it was situated to the north of the major town
(“Bei” means “north” in Mandarin Chinese). The other theory is that because the island was situated at the northern entry point of Qingfeng Pass. Historians still disagree on which theory is more plausible. What we do know now is Beimen Island was located in the middle of a crucial transportation channel. Boats which travelled north from the numerous ports in Taijiang Lagoon to various large harbors along the seacoast had to pass this island. Locals also traveled to and traded with Penghu Island and Taipei on their simple sampans.
After the island connected to Taiwan during the Daoguang Period, salt fields began to appear rather quickly. As stated in The Records of Exclusive Salt Sales in Taiwan (台灣鹽專賣誌) , the “Laitong Salt Field was established on the 21st year of the Qianlong Period, but was abandoned not long after. Between the end of the Qianlong Period and the beginning of the Jiaqing Period, the salt field was re-established at Zhuzi harbor at Qigu Town under the same name. But then it was flooded. During the 23rd year of Jiaqing Period, the salt field was relocated at Jingzaijiao, again under the same name.”
The year 1895 marked the beginning of the Japanese Occupation Period. The Japanese government abolished monopoly on salt and did not actively manage the industry, either. Salt fields were gradually abandoned. It wasn’t until four years later, when the Japanese government re-established salt monopoly, did the salt fields in Beimen Township began to thrive again. Operating salt fields at that time included Wangyegangtian salt field, Keliao salt field, Jingzaijiao (formerly known as Laitong salt field) salt field, and Beimen salt field. At the beginning of this period, Beimen Township was the only fishery port in Tainan County, seafaring, fishing industries and salt production was very popular and prosperous at the time.
The Japanese originally established the area as “Beimen Island Subprefecture”. However, the harbor gradually silted up and lost its original purpose. The area was then transformed into a simple salt production village. The island, after connecting with Taiwan, belonged to Xuejia Fort which later became “Beimen Village” during the Japanese Occupation Period. The area was renamed “Beimen Township” with the beginning of the Republic of China Period (1945). Beimen Township, Qigu Township, and Jiangjun Township are the three major coastal fishery and salt townships of former Tainan County. The name was changed to Beimen District after the merging of Tainan County and City.