Daishan County, under the Zhejiang Zhoushan City. Located in the northeast of Zhejiang Province, in the middle of Zhoushan Islands, between 30°07 '-30°38' north latitude, 121°31 '-123°17' east longitude. North and Shengsi Islands border, east of the open sea, south and Zhoushan Island. There are 571 islands in the county, of which 16 live islands, Daishan Island is the largest, with a land area of 104.97 square kilometers. The total area is 5242 square kilometers, including 326.50 square kilometers of land (including 57.40 square kilometers of intertidal zone) and 4915.50 square kilometers of sea area. By the end of 2013, it has jurisdiction over 6 towns and 1 township: Qushan Town, Gaiting Town, Dongsha Town, Daxi Town, Changtu Town, Daidong Town and Xiushan Town. According to the seventh census data, as of midnight on November 1, 2020, the permanent population of Daishan County is 207,982 people.

In 2019, it was selected as the second batch of counties (districts) that reached the standard of water-saving social construction and the top ten counties (cities) with national investment potential in 2019. In May 2020, it was selected into the county new-type urbanization construction demonstration list. In July 2020, the National Health Care Committee confirmed Daishan County as the national Health County in 2019.
In 2020, the GDP of Daishan County was 38.48 billion yuan, calculated at comparable prices (the same below), an increase of 58.1% over the previous year. The value added of the primary industry was 3.63 billion yuan and that of the secondary industry was 25.60 billion yuan. The added value of tertiary industry is 9.25 billion yuan, and the ratio of tertiary industry structure is 9.4:66.5:24.1.