Zijin County, under the jurisdiction of Heyuan City, Guangdong Province, is located in the east-central part of Guangdong Province, the southeast part of Heyuan City, the east bank of the middle reaches of the Dongjiang River, and the upper reaches of the Hanjiang River. It is the birthplace of the Hanjiang River. With a total area of 3635.13 square kilometers, it is located in the subtropical monsoon climate zone. In 2020, there will be 16 towns and 270 village (residential) committees. The county government is stationed in Zicheng Town. According to the data of the seventh population census in 2020, the permanent population of Zijin County is 469100. It is a pilot project of fiscal reform in counties directly under the jurisdiction of Guangdong Province.

Yong'an County was approved by the court in 1569, the third year of Longqing in the Ming Dynasty. In the third year of the Republic of China (1914), Yong'an County in Guangdong Province was renamed Zijin County. In May 1949, it was subordinate to Dongjiang Special Area. In 1952, it was changed to the East Guangdong Administrative Region, in 1956 it was changed to the Huiyang Special Region, in 1959 it was changed to the Shantou Special Region, in 1963 it was restored to the Huiyang District, and in 1988 it became the county under the jurisdiction of Heyuan City.

In 2019, Zijin County was listed as the first sub-county for the protection and utilization of revolutionary cultural relics. In 2022, the GDP of Zijin County was 14.778 billion yuan, up 2.6% year on year.