Yanshan County is under the jurisdiction of Wenshan Zhuang and Miao Autonomous Prefecture of Yunnan Province. Located in the southeast of Yunnan Province, there are more than ten ethnic groups including Han, Zhuang, Yi, Miao, Hui and Yao living in the area, which is a state-level poverty-stricken county. The county covers an area of 3822 square kilometers, governs four towns and seven townships, 86 village committees and 22 communities. According to the data of the seventh population census, as of 0:00 on November 1, 2020, the permanent population of Yanshan County was 476587.

Yanshan County is named for its "beautiful mountains and its shape is like an inkstone" near the county seat. On September 25, 2018, it was awarded the honorary title of "2018 Comprehensive Demonstration County of E-commerce in Rural Areas" by the Ministry of Commerce. On April 30, 2019, the People's Government of Yunnan Province decided to withdraw Yanshan County from the poverty county sequence. On December 6, 2019, it was selected as the pilot unit to promote the quality of national farmers' cooperatives in the whole county.

In 2020, Yanshan County's GDP reached 17.839 billion yuan, up 6.2% year on year; The investment in fixed assets was 13.023 billion yuan, up 44.3% year on year; Local public budget revenue was 867 million yuan, up 3.1% year on year; The per capita disposable income of urban permanent residents was 36213 yuan, up 4.1% year on year; The per capita disposable income of rural permanent residents was 12705 yuan, up 8.1% year on year; The balance of deposits and loans of financial institutions was 13.22 billion yuan and 10.576 billion yuan, up 30.84% and 24.96% respectively.