Sinan County, under Tongren City of Guizhou Province. Located in the northeast of Guizhou Province, west of Tongren City, Wuling Mountain hinterland. It borders Yinjiang Tujia and Miao Autonomous County in the east, Fenggang County in the west, Shiqian County in the south and Dejiang County in the north, with a total area of 2,230.5 square kilometers. In 2020, Sinan County has a registered population of 668,300. The main ethnic group is Han, among which the ethnic minorities are Tujia, Yi, Bai and so on. As of October 2021, Sinan County has jurisdiction over 3 subdistricts, 17 towns and 8 townships.

In the fifth year of Jian 'an of Han Dynasty (200 years), Liu Zhang of Yizhou divided Fuling County into Danxing County, Hanjia County, Yongning County, Yongning County in today's Sinan area. In the 3rd year of the Republic of China (1914), Sinan Prefecture was changed into Sinan County. In 2011, it was Tongren City. On March 3, 2020, the People's Government of Guizhou Province approved Sinan County to withdraw from the poverty-stricken county list.

In 2020, the GDP of Sinan County was 17.478 billion yuan, an increase of 4.2% based on comparable prices. Among them, the added value of the primary industry was 4.562 billion yuan, and that of the secondary industry was 4.173 billion yuan. The added value of tertiary industry is 8.743 billion yuan, and the structure of tertiary industry is 26.10:23.88:50.02.