Yanyi Town, a town under the jurisdiction of Mentougou District, Beijing. It is located between longitude 115°43′13″~115°57′45″ East and latitude 39°57′54″~40°10′39″ North. It is located in the central mountainous area of Mentougou District, neighboring Miaofengshan Town and Wangping Town to the east, Daitai Street to the south, connecting with Zhaitang Town to the west, and bordering with Laoyugou of Changping District and Huailai County of Hebei Province to the north. The town area is 263.2 square kilometers. During the Ming Dynasty, there were already villages in Yanyi area.In 1958, Qingbaikou People's Commune was established.In 1984, the commune was changed to a township.In 1994, the former 2 townships of Dacun and Tianzhuang were merged to form Yanyi Township. As of late 2018, Yanyin Township had a household population of 9,176. As of October 2019, Yanyi Township has 1 community and 23 administrative villages under its jurisdiction, and the township government is located in Fujiatai Village, Yanyi Township. In 2011, the total financial income of Yanyi Town was 0.7 billion yuan, of which 730,000 yuan was local financial income. From the point of view of each major tax, the completion of sales tax 588,000 yuan, value-added tax 34,000 yuan, enterprise income tax 18,000 yuan.