Back in the New Stone Age, Ninghai was already home to the primitive people. In 280 AD (West Jin Dynasty) it was established as a county, with the seat at Baijiao. But when time elapsed into the year 589 ( Sui Dynasty), it ceased to be a county and became part of the Linhai County. In 621 AD it was restored as a county, seated at Haiyou (part of the present Sanmen County). Later it was merged into the Zhang’an County. In 689 AD when Empress Wu Tse-Tien took the throne, she had it restored, with the county seat placed at Guangduli (the present Chengguan Town). In 706, the expanse in the east of the county was put under the jurisdiction of the Xiangshan County.
In 1940, or the 29th year of the Minguo Period, a new county Sanmen was established, which comprised 17 towns, including Haiyou town. After its establishment as a county, Ninghai had successively been part of Linhai Prefecture, Taizhoulu Prefecture, and Taizhou Prefecture. When the PRC was founded in 1949, this piece of land was first under the Taizhou Prefecture, and later was part of Ningbo Prefecture and Taizhou Prefecture. But in October 1958, it was abolished as an independent county and was incorporated into the Xiangshan county, with the seat set at Liyang and then at the Chengguan town of the former Ninghai. In Oct 1961, it was reestablished as a county under the Ningbo Prefecture that turned into Ningbo City in July 1983.
Ninghai has produced a galaxy of celebrated people in history, who were upright and unyielding. In late South Song Dynasty, the Privy Council Secretary Zheng Lin, the Right Prime Minster Ye Mengdin and the historian Hu Sansheng, litterateur Shu Yueyang took official posts in the Court, together with the powerful minister Jia Sidao. As the three disdained to cling to the Jia’s cult, Zhen was killed by Jia and Ye. And Hu and another official named Shu Yuexiang discarded the feudal governmental posts because of conflicts with Jia and indulged themselves in academic studies thereafter.
Fang Xiaoru was a Ming official and scholar who wrote several works and advised his emperor. After Fang's emperor fell from power after a civil war in 1399, Zhu Li, the conquering leader, asked Fang to write the law legitimizing his succession. Fang refused and was tortured and killed along with his relatives, friends, associates, students, neighbors and anyone with the most remote connections to him. In addition, a de facto ban was placed on all of his works. His unyielding deeds made him become a national hero and has been venerated in China ever since. Rou Shi, one of the five martyrs of the Left Wing Literature League of modern times, was heroine enough not to yield to the Kuomintang regime and was killed in Longhua, Shanghai. In Anti-Japanese War in the 30s and 40s of the 20th century, Kong Yong, the security force leader of Haichuan, Jiangsu also sacrificed his life for the revolutionary cause.
The great artist Pan Tianshou has been very much remembered for his integrity and lofty morals.